Horizon (1964) s53e10 Episode Script
Should I Eat Meat? - The Big Health Dilemma
1 MELLOW, SEDUCTIVE MUSIC Fine roast beef, cooked to perfection.
Plump sausages, pan-fried and golden brown.
Luscious lamb chops, grilled until pink and tender.
This isn't just ordinary meat.
Depending on what you've recently read or heard on the news, this is either a protein-rich and nutrient-packed dietary necessity MUSIC: "Little Red Rooster" .
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or an artery-clogging, life-shortening food to avoid.
I am genuinely confused and would dearly love to separate fact from fiction because for many of us, meat is a pleasurable part of our daily diet.
Now as a family, we like meat.
We eat it most days - chicken, lamb, beef, pork and of course, bacon and burgers.
And we're not alone.
Worldwide meat consumption has nearly doubled in the last 50 years.
That's certainly how a burger should look.
That's a very good burger.
Could something that is so ingrained in our culture really be killing us? I'm going to track down the eminent scientists who study the impact of different types of meat.
I want to find out what they've discovered but also what they themselves eat.
Just what is the truth about meat? It's really early in the morning.
It's cold, it's dark and I am off to see more meat than I have EVER seen in my life.
In the last few years, meat has hit the front pages but for all the wrong reasons.
Frankly, I'm sceptical about many of these headlines and want to find out what's behind them.
Does meat really give you cancer? Whoa, right! Oh, that looks like an alien growth! Will eating it shorten your life? Those who consumed higher amounts of red meat had higher risks of total mortality, cardiovascular mortality and cancer mortality.
Is it a killer, or are these claims greatly exaggerated? You're probably looking at about a difference of five years, four to five years in life expectancy.
As well as investigating the latest science, I'm going to put myself on a high-meat diet to see what, if any, effects it has on my body.
This is where a lot of the meat on our tables comes from, a huge meat wholesaler.
Here they prepare up to 30 tonnes of beef, pork and lamb every day.
It gets sent out to butchers and ends up on our dinner plates right across the nation.
That's impressive, impressive speed at which you go.
Blimey.
Does being around all this meat put you off it at all? Definitely not, definitely not.
I've got a very good appetite for meat.
How often? What, do I eat meat? Yeah.
I don't consider it a meal unless it's got meat in it, really.
For people like Pete, in fact for most of us, eating meat is a normal thing to do.
What's more, it has lots of good things in it.
Meat provides some really important nutrients that are essential for health, so mainly protein.
Meat is protein-rich and protein is very important in terms of repair of your body.
And there's also some micro-nutrients such as .
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iron which is good for helping us to have healthy red blood cells that help to transport oxygen around the body.
Also B12, which is also involved in the working of our blood cells.
B vitamins particularly sometimes can be very difficult to get from a plant-based diet.
And zinc which is important for healthy hair, nails, and also has a role in wound healing and sort of helping us to repair ourselves.
If you don't have meat in your diet, you can certainly still get all the nutrients that you need but you do have to think a little bit more about how you get those.
As a species, we evolved eating meat, though probably not that much or that often.
But how much is too much? Well, to find out you need to do big studies - lots of people followed for many years.
It's those studies that I'm going to look closely at.
Together, they involve almost a million people and for the most part, they're looking at particular types of meat.
There is little evidence that chicken and other white meats pose a health risk so these are off the agenda.
Really, the meats that are under fire are red meat and processed meat.
Now red meat includes beef, lamb, pork, while processed meat could mean salami, bacon, sausages - so those are the meats that I'm going to focus on.
Now I eat relatively modest amounts of meat but would it matter if I ate more? To find out, I'm going to go on a high-meat diet.
I'm going to eat about twice the advised daily amount, something that around 25% of the adult male population in Britain already do.
So let's see what I'll be eating more of.
Red meat is stuff like steak, lamb or pork chops and ground red meat like beef mince, whereas processed meat has been preserved by salting, smoking or by adding preservatives - things like salami, sausages and ham.
On average, Brits eat about 70 grams of red and processed meat every day.
That doesn't include chicken or any other poultry, but about a quarter of British men eat around 130 grams so I'm going to adopt their diet.
Now I think that on average I probably eat 65-70 grams of meat a day, but for the next month I'm going to be going up, nearly doubling it.
So what does 130 grams of meat look like? Well, something like this.
It could be a couple of bits of bacon in the morning for breakfast and a burger in the evening.
That's 130 grams.
Or you simply have a piece of steak about this size or maybe a pork chop this size - that's 130 grams.
Or you might go for one sausage plus a couple of bits of ham for lunch.
And if you're wondering how much that adds up to over the course of four weeks - well, it's about this much.
And frankly that looks quite doable.
To monitor how this seemingly moderate amount of meat affects my body, I've come to the Food and Nutritional Sciences Department at Reading University.
Hello there.
Michael.
Hello.
I'm going to have a health check before and after the diet to see if a bit of extra meat changes anything.
What's happening at the moment is I'm about to have some blood taken so they can measure my cholesterol and they're also going to put me on the weighing machine over there so they can measure things like body fat, weight, things like that.
Oh, yes, felt that one.
And the idea is to get a baseline figure so that before I go on my enhanced meat diet, they've got some figures.
I'll come back here in a few weeks' time, they'll do it all over again and we'll see if the meat has made that much of a difference.
I'm just a sample size of one so the results will be very personal and not representative of everyone.
Desirable ranges should be in the fat percentage between 11 and 22% and you are 15.
3 so you're well within the desirable range.
I'm desirable.
For a rather more scientific way to assess the impact of meat, I've come to Southern California.
Here they've been conducting one of the longest studies ever into the effects of diet and lifestyle on health.
I'm in Loma Linda which is in California near Los Angeles and I'm here to meet the Hucksey family who are part of an unusual group of people.
They're unusual because their religious beliefs seem to contribute to their impressive longevity and general good health.
Hello, good morning, hello.
Very nice to meet you.
Welcome, please come in.
Thank you very much.
Hiya, gang.
This is my family.
Hello.
Wife Danielle.
Hello.
Hello.
The Huckseys are Seventh Day Adventists, a Protestant sect founded in the 1800s.
Even though it's Saturday, we're off to church because that's when Seventh Day Adventists observe the Sabbath.
CHURCH ORGAN PLAYS Now Seventh Day Adventists like the Huckseys live considerably longer than the average American.
CONGREGATION: # Safe within his hand that guides us Hidden in That's probably because they believe that leading a healthy, wholesome lifestyle is what God wants them to do.
In the Bible, in 1st Corinthians 6, there is a verse that talks about our body is the temple of the Holy Spirit and that we should use our bodies for the glory of God, and that we are to take care of our bodies so that we can not only live longer but also be more helpful to other people while we ARE living.
We're sitting down to a different kind of breakfast because their religion encourages vegetarianism.
So can you tell me what I'm looking at here, then? So this is - it looks like scrambled eggs but it's not, is that right? Scrambled tofu.
OK, scrambled tofu, and these, I'm guessing, are not pork sausages? No, those are Saucettes, so another soy-based vegetarian.
OK.
Heavenly Father, thank you for the chance to enjoy the Sabbath day and the food that you've prepared.
Please bless our time together in Jesus' name, amen.
Amen.
The Huckseys are strict vegetarians but because their church only RECOMMENDS a veggie diet, many of the Adventist community eat some meat.
Is it primarily religious, or ethical, or was it health? It was health and I wanted my kids to be healthier.
I think often as parents, you do things for your kids that you wouldn't do normally and I wanted them to be healthier.
And now that I have an eight-year-old, I think I want to live a long time for him and be healthy for him.
You look at products that God has created, such as a grapefruit, whole grains, sweet potato.
The closer you look at them, you realise how beautiful and nutritious they are.
Not only is it showing that Adventists are living seven years longer, but the quality of those elderly years! How long do you expect to live till? My grandmother just passed away at 103.
OK, right! That's impressive! CHURCH BAND PLAYS What makes Adventists of particular interest to scientists is that although half are vegetarian, around half eat meat so the two groups can be compared.
And unlike the wider population, Adventist meat-eaters tend not to be heavy smokers or drinkers, factors which CAN influence any comparisons between vegetarians and more red-blooded Americans.
Since the 1950s, scientists at Loma Linda University have been conducting numerous health studies on Adventists.
The most recent have been trying to identify the health habits of the long-livers.
I am here to meet Dr Gary Fraser who's been leading this research for three decades covering over 150,000 Adventists.
These huge epidemiological studies track people's diets and lifestyles and look for associations between what they eat, their overall health and what eventually kills them.
Hello.
Hi.
Hi, Mike Mosley, hello.
Nice to meet you.
I'm joining the good doctor for lunch and as I'm on a high-meat diet, our choices couldn't be more different.
OK, so differences in what we've got here, then.
I've got pulled pork while Dr Fraser has a vegetarian salad with nuts.
I have to confess, I had bacon for breakfast as well.
OK.
I had four rashers of bacon.
Wow! All right.
I hope you survive this experiment.
Thank you! So kind of broadly, what have your studies revealed? That when you look at cardiovascular risk factors in a broad sense - diabetes, hypertension, being overweight, having increased blood lipid levels - that the vegetarians are doing better than the non-vegetarians.
And indeed that has translated in most of the studies to the vegetarians having a lower risk of heart attack and cardiovascular disease, so that whole area, I think, is fairly well established.
Dr Fraser found that men in the study who ate beef at least three times a week had double the risk of fatal heart disease compared to the vegetarians.
And this apparently massive risk to health was in people eating under 60 grams a day, which is less than your average Brit and half what I'm currently eating.
So you have found that even eating what some people would regard as quite a modest level of meat makes a difference.
Yes.
I mean, how big a difference? You know, I don't think we have all of the answers on that to be very precise about it and of course your plate of food there has got some things on there that go beyond the meat that I wouldn't necessarily recommend.
So let me put it this way.
That plate as compared to this plate, where I have replaced the meat with nuts and with whole-grain bread and so forth, our evidence says that you're probably looking at a difference of five years, four to five years in life expectancy.
The Adventist studies certainly suggest that vegetarians lead longer and healthier lives, and Dr Fraser makes a compelling case for avoiding meat.
So is that the end of the story? Well, no.
For starters, if meat is as bad for you as the Adventist study suggests, what's in it that is doing the harm? Let's take the five most popular meat products in the UK by volume purchased.
They are whole chicken, bacon, pork sausages, pork sliced cooked meats - things like ham and salami - and beef mince.
Since we are concentrating on red and processed meat, I want to compare bacon, pork sausages and beef mince with some vegetarian options, to find what's in the meat that could be damaging our health.
Dr Orla Kennedy is a nutritionist and dietician at Reading University.
She's chosen three popular vegetarian foods commonly eaten instead of meat to do a head-to-head comparison.
We've got vegetarian sausages, we've got tofu, OK, made from soya bean curd and then we've got cheese, good old-fashioned Cheddar cheese.
None of it looks terribly appetising, does it, in a kind of cold state laid out? No, no, not quite.
Maybe the cheese looks the tastiest there right now, definitely.
Well, the tofu - maybe not.
Before I turn to the bad, I want to look at the good.
Let's start off by looking at protein.
What's the protein content of these different foods? Beef mince has the highest amount of protein and it's good high-quality protein.
Not far behind that is the cheese, OK, quite high in protein as well.
Cheese has just over 25 grams of protein per 100 grams, only slightly behind the beef mince.
Vegetarian sausages and ordinary sausages, there's not much difference between them.
Interesting that both the pork and veggie variety contain almost the same amount of protein.
And the tofu is last.
That's going off the pedestal.
What's interesting in terms of the red meat is proteins are made up of amino acids and there are a number of amino acids which are essential which the body can't make but actually meats provide these, so meats are a complete set of proteins, whereas you won't get that in the vegetarian or the kind of tofu alternatives.
What many people probably don't realise is that meat can be richer in micro-nutrients than vegetables, particularly when it comes to some of the less well-known vitamins.
So what about vitamin B12? Now that's one of my favourite vitamins, not terribly well-known vitamin or talked about but associated with brain development.
I like my brain.
So king of the B12s is the beef again.
Surprisingly, actually - cheese is quite high.
It's very close.
You get three micrograms of B12 in every 100 grams of beef mince.
The cheese offers almost as much but the other veggie options tested have absolutely none.
So far, the meat's doing well but how does it fare when it comes to the Lord Voldemort of the diet world? And finally, saturated fat.
Saturated fat.
It's actually the cheese that has the highest amount of saturated fat.
That's over 20 grams of saturated fat per 100 grams of cheese.
That's surprising.
That is surprising.
However, the recommendations in terms of portion sizes are - for cheese it's a lot less, so a typical portion is about 30 grams.
People tend to eat less cheese than they do meat and the other vegetarian foods being tested have hardly any saturated fat, certainly compared to the fat.
Beef mince, the bacon rashers and the pork sausages have almost the same level of fat.
They're all much of a muchness.
And that muchness is a considerable amount of saturated fat.
They all contain around 16 times the amount found in the tofu.
So while meat tends to deliver more nutrients and micro-nutrients, on the whole it also contains more saturated fat.
And it's the high levels of saturated fat you find in red and processed meats that gives them their unhealthy reputation.
The actual reasons why we see an increased risk of coronary heart disease with a higher intake of red meat and processed meat, we don't really know exactly but there are several suggestions as to why that could be.
So firstly it could be the saturated fat content that we see in say fattier red meats and also processed meat.
Saturated fats mainly come from animal sources so animal fats, things like lard, dairy fats, butter.
These are all things that are high in saturated fats.
They're the fats that you get around meat so around your chop, under the skin of chicken and also marbled through steak.
Some red meats tend to have about 50% of the fat comes from saturated fat, and 50% from unsaturated fat.
This is saturated animal fat.
Now unlike vegetable oil, this is fat that is solid at room temperature.
For decades, we've been told that eating saturated fat leads to elevated cholesterol, to heart disease and then eventually to death but it's perhaps not quite as simple as that.
It was back in the 1950s when research in the USA started to show a link between saturated fat and heart disease.
'The chemist heats a sample in an oven 'and pours the fat into a flask.
' At the time, red meat was considered to be a healthy and wholesome part of our diet.
'Prepared meats are easy to serve and good to eat.
'They are enjoyed by almost everyone, everywhere, every day.
' But when the connection between fat and heart trouble was made, red and processed meat were firmly in the firing line.
By 1955, fat had become such a big issue that when President Eisenhower suffered a heart attack, one of the first things his doctors did was put him on a low-fat diet.
Red and processed meat went from something we enjoyed to something that could carry us off to an early grave.
For years, studies continued to reinforce the apparent link between saturated fat and heart disease.
It seemed we would never again eat meat without feeling our arteries groan.
Saturated fat and, by association, fatty meat continued to be the big bad villain well into the 21st century but in the last couple of years new studies have thrown that association into question, suggesting saturated fat might not be quite so bad after all.
One of the most influential people behind this research is a doctor who works in Berkeley, just across the bay from San Francisco.
What he and others discovered has shaken confidence in some of the advice that has been mainstream for decades.
Dr Ronald Krauss is a world expert on diet and health.
Ever since he graduated from medical school, Dr Krauss has been researching the impact that cholesterol and diet have on heart disease.
We're meeting for breakfast and, as I'm still on my special diet, I'm on the hunt for meat, not always as easy as it sounds.
I'm actually looking for bacon.
Do you see the words bacon? Bacon? This is a Jewish deli, so Oh, right, I'm not going to - I'm not going to see bacon here! They might have it.
It's a Jewish deli.
But I wouldn't count on it.
For years, Dr Krauss was an adviser to the American Heart Association and a firm believer that higher saturated fat meant a higher risk of heart disease.
But when he tried lowering people's cholesterol levels by putting them on low-fat diets, he got a nasty surprise.
We thought that everybody would get better on this diet, that their cholesterol profile would improve.
What we found was that the average man, whom we were studying, with a normal profile to start with, actually got worse.
Not surprisingly, this made Dr Krauss question whether saturated fat was quite as bad as everyone believed.
So he re-analysed 21 separate studies that looked at saturated fat and heart disease.
His new analysis found no obvious link.
When I first read your paper, which was a while ago, it was a shock and a revelation at the same time, because, you know, I was also convinced saturated fat must be bad.
Looking at all the studies, on the average, there was no net effect of saturated fat per se on heart disease risk, so heart-attack risk was slightly higher but not significant.
Stroke risk was actually reduced and so overall if you took it across a fair range of disease, heart disease and stroke, there was absolutely zero effect on those conditions.
Others have come to a similar conclusion.
Now that doesn't mean saturated fat is a health tonic but it does suggest the fear of saturated fat has been overdone.
But is there something else in red meat that could be clogging our arteries? So we know that there is an association between high intakes of processed meat, red meat and heart disease but we don't really know why.
Of course the evidence with saturated fats has changed in recent times and so this kind of makes the whole arena much more interesting but a little confusing.
And I think it's very important that we understand the mechanisms before we jump to conclusions about what we do about it.
And so it will be very interesting to see what we learn next about the connection of red meats and cardiovascular diseases.
Dr Krauss is currently involved in new, more controversial, research into meat coming out of the Cleveland Clinic.
It suggests that, yes, there is an ingredient in red meat that could increase your risk of heart attacks but bizarrely, it's concentrated not in the fat but the lean part of the meat.
It's a nutrient called L-carnitine which is abundant in red meat, like the steak Dr Krauss is cooking me for lunch.
Carnitine was really the substance that led to concerns about meat.
It does appear to have effects on the build-up of cholesterol in the cells that form plaque in the arteries.
This research suggests that L-carnitine can react with bacteria in our gut to produce TMAO, a substance that can slow down removal of cholesterol from our arteries.
It just happens that the bugs that live in our intestine seem to like to eat carnitine and they happen to produce this substance and they don't care what happens after that.
So the TMAO, which are the kind of bacteria, have kicked off and are then going to be going into my arteries and they're going to be clinging onto the fat - that's right? That's kind of the hypothesis, that's the theory, is it? That's the hypothesis.
It's still early days but research on animals has shown that feeding them carnitine does lead to clogged arteries.
This is not something that has been proven to occur in our bodies but it's a potential mechanism for how this might work.
Ironically, we now have evidence that saturated fat isn't so bad and that lean meat which we've been advised to eat instead could be doing damage.
The L-carnitine hypothesis is very, very interesting - it certainly gives us another avenue to explore.
But I think what's interesting is that it may not be the obvious offenders as we first thought they were, the saturated fat and the salt.
They might be important for other reasons but it might be this other thing, when we're talking about meats, that is actually the problem.
At the moment, the jury is still out about what it is in meat that can increase your risk of cardiac problems and also how big the risk really is.
So where does that leave me? At this moment in time, pretty confused.
As I tuck into yet another burger as part of my high-meat diet That's how a burger should look, right there.
It's clear that unearthing the truth about meat is far from straightforward.
That's a very good burger.
As well as health, meat is about our culture, who we are.
We have to be clear that there are things above and beyond the health effects of foods that are very important to us.
There is something about its place in our culture, in our society.
It's a sign of affluence to be able to put meat on the table every day.
Meat is also seen as quite a centrepiece to a meal.
So if you think about Christmas or a Sunday roast, you usually have a big piece of meat in the middle of the table so a lot of families bond around that meal.
So far, I've heard from two experts with radically different points of view.
I still don't know how much meat is safe to eat.
And amongst our favourites of beef, pork, mince, sausages, bacon and ham, are some clearly worse than others.
Looking for more answers, I've come to Boston.
At Harvard University's School of Public Health, they've recently completely the world's longest-ever study looking at the health effects of eating different foods.
As part of it, the researchers also looked at red meat and processed meat separately, to assess their relative impact.
The research is the life's work of the man some call the father of nutrition epidemiology, Dr Walter Willett.
So, this is kind of healthy food, yes? Yes, this is I think a very good option of healthy alternatives and the food service here has been really great in terms of trying to offer what we see to be important for health outcomes.
Enjoying the cartoon up there.
Makes you look a little like Colonel Sanders of Kentucky Fried Chicken fame.
No relationship.
Dr Willett and his team have been following the diets of over 100,000 people for over 30 years, another huge study.
The results were clear, starting with those for unprocessed red meat, basically fresh meat like minced beef, steak and chops.
We found in this population of about 120,000 men and women that those who consumed high amounts of red meat had higher risks of total mortality, cardiovascular mortality and cancer mortality.
Right, so they died of heart attacks and they died of some cancers? Yes.
They found eating red meat had a relatively modest impact.
85 grams a day, the size of an average beef burger, was associated with a 13% increased risk of premature death.
Eating processed meat was much worse.
If you had steak, burgers, and then you have kind of bacon and hot dogs over here, which is the worst? Processed meat like bacon and boloney and sausage are ounce-for-ounce several times worse.
In fact, the study suggested that eating about 35 grams of processed meat a day - a couple of rashers of bacon - was associated with a 20% increased risk of premature death.
This was mainly because of an increased risk of heart disease and cancer.
Bad news, considering three of the UK's top five favourites, bacon, pork sausages and ham, all fall into THAT category.
How has your research affected how you eat? I grew up in the Midwest and red meat was part of our diet probably three times a day.
And on most days, we often had it for breakfast in one form or another, sandwiches, hot dogs at school and usually hamburger, meat loaf, something like that at dinner time.
But my diet has changed quite a bit in that way, as we've seen the data come in, that I have red meat maybe a few times a year.
I'm not a strict vegetarian.
A few times a year? A few times a year.
Well, that was actually very disappointing, particularly as I'm on this high-meat diet, because I was hoping for just a few crumbs of comfort but Dr Willett had almost nothing good to say.
Things are looking grim for lovers of burgers, beef and bacon.
But just when I thought things were becoming clearer, I came across another study and its findings don't quite match up with Dr Willett's.
The European Prospective Investigation into Cancer and Nutrition, or EPIC for short, followed even more people than the other studies I've looked into though for a shorter period, 12 years.
When you compare it to the American studies, there's a striking difference in their findings.
Now these are the results of the so-called EPIC study and it really was epic.
The researchers followed half a million people in ten countries for more than 12 years, and their conclusions are very different to the Harvard study.
They found that eating moderate amounts of red meat had no effect on mortality.
In fact, they conclude that "a low - "but not zero - consumption of meat might be beneficial for health.
"This is understandable as meat is an important source of protein, "iron, zinc, B vitamins, vitamin A "and essential fatty acids.
" In other words, eating small amounts of red meat seemed to be better for you than being a vegetarian.
So, the Harvard study found a modest association between moderate red meat consumption and early death, the European study didn't.
The red meat argument is slightly less clear at the moment.
We wouldn't expect two studies to have identical results.
However, in general, when studies have different results, it can be difficult to pinpoint the exact reason for the difference, so we're not as confident that there is a real association between red meat and early death.
And the fact is that observational studies like these can never really prove that specific dietary habits cause a disease.
These types of studies can find associations between dietary components, for example, red meat and disease, but we can't absolutely prove for certain that it is the dietary component that is causing the disease.
In light of the varied results of these long-term studies, just how much red meat do the experts I've met think we should be eating? If one is able and comfortable to have no red meat at all is a good thing.
However, you know the population is not going to become vegetarian.
Um, and so I think one starts with the concept of meatless days.
It looks like having red meat quite infrequently, say once a month, is really an optimal diet.
It's good to think of it as a special event, like, I don't know if you consider here, but in New England, lobster is a special event.
It's not something that we have on an everyday basis.
We think that lean meat in particular is not a hazard to health if it's consumed in moderation.
From the evidence so far, what I conclude is that eating a lot of red meat every day is not a great idea.
But a modest amount a couple of days a week is unlikely to do you much harm.
Now, before meat-eaters go off rejoicing, there is a sting in the tail, because both the EPIC study and the Harvard study found that eating moderate amounts of processed meat, that is, bacon, sausages, salami, did have a significant effect on your risk of getting heart disease and cancer.
So, just how might processed meat cause cancer? Here at St Thomas's Hospital, they see hundreds of patients each year who are suspected of having colorectal and bowel cancer.
It is the third most common cancer in the UK and the one that has the clearest links to a high-meat diet.
Consultant gastroenterologist Dr Jeremy Sanderson uses a colonoscope to check for early signs of bowel cancer.
It's a flexible tube with a camera attached inserted into the rectum and guided around the bowel, giving remarkable high-definition pictures inside the body.
He's keen to show me how the equipment works.
Much to his disappointment, I turn down the opportunity for a personal examination.
This is a standard Olympus colonoscope.
As you can see, it's about a metre and a half long but you'll be pleased to know we don't usually need to use all of that instrument.
OK, how far do you go then normally? Normally, because the bowel is quite flexible, and in some people you can get almost all this telescope coiled up into the bowel if your bowel's very flexible, and that's the art of colonoscopy, is to be able to straighten it, concertina the bowel down.
We sometimes say it ends up at the end of the treatment looking a bit like a question mark shape.
What are you looking for? We're looking for the "polyps" they're called, they're little tiny mole-like growths on the lining of the bowel and steadily what happens over a period of five, ten years, those little growths turn, get bigger, and a bigger polyp, and finally can become a cancer.
This is the view Dr Sanderson gets when he's searching for polyps in the large bowel.
So, what am I looking at, at the moment? Well, essentially thisthis is a normal colonoscopy so you're looking at the lining of the colon, you know, down the end of the instrument.
It's a sort of very high resolution video camera.
How far up, so to speak, are we? We're about 40cm up.
As you can see, the nice normal smooth lining, you can make out blood vessels.
In fact, when the bowel's altered or inflamed, one of the first things that goes is the ability to see the blood vessels in such detail.
The architecture is very strange, isn't it? But things look very different when the patient has an abnormal bowel.
Whoa, right, I had no idea.
That That is a polyp, is it? That is a polyp.
So what you're seeing here, and in fact you can see it's on a stalk Can you see it here? Oh, wow, there you go.
Here's another one.
Oh, that looks like an alien growth.
Yes, it's grown to a size.
And that started It looks huge.
Well, that's about that's about 2cm.
It started as a small, little polyp.
It grew, it grew and it's pulled a bit of the lining with it.
How old would this person be? This person is in their 50s.
You'd come across that and you're going, "That's abnormal.
" If the polyps aren't removed, they can turn cancerous.
Why might a diet rich in meat lead to polyps? Wellas doctors always say, it's complicated.
There are various factors in meat, particularly in processed meats, chemical factors that have been shown to promote cancer or to promote increased growth of cells.
In light of what I've heard from other experts, I'm curious to find out what Dr Sanderson himself eats.
Do you eat red meat? I most certainly do eat red meat.
I believe in being an omnivore.
I don't think I'm an excessive meat eater.
OK, define excessive.
Well, I think I'll have I'll have maybe haveyou know, two bits of red meat each week.
If I was going to make one change to my diet, I think it's the reducing those processed meats that is the one good opportunity and then you can keep your roast beef and yourand your steak.
Dr Sanderson thinks the most effective way to prevent bowel cancer is to have a colonoscopy in your mid-50s, so any polyps can be removed.
What we've done here is we have delivered this snare wire around the polyp and it's sitting on the stalk, and we've tightened it and now you'll see we're going to apply a current to this stalk, and then you'll see some smoke and burning generated.
That's all on the end of the endoscope? Yes, so we're just tightening it and thenthere it goes, and that's it, polyp gone.
It's gone, "pop".
We call that an ex-polyp.
So, what is it that makes processed meat like ham and bacon potentially carcinogenic? What's in it that could promote the growth of cancerous polyps? I'm back at Reading University's Food and Nutritional Sciences Department to find out.
And what better way than to actually make some? Dr Danny Commane is a specialist in gut health and colorectal cancer.
He's gathered together everything we need to turn pork into bacon, the nation's, and my, favourite processed meat.
Hi there.
Hi, Michael, we're going to cure some bacon, I'll give you the gloves.
I've never done this before.
OK, so, we've got some sea salt and we need 12 teaspoons of it.
12?! blimey! OK.
Yeah.
It's only when you make it yourself you realise how much salt there is in it.
Yeah, that's right.
Sugar, how much? So, five teaspoons of sugar, and we've just got curing salt which contains our sodium nitrite.
OK, it's not encouraging, it says, "toxic if not used correctly", and how much of this stuff? I'll be careful with this.
Just one teaspoon.
And then, presumably, you just mix it up, do you? That's right, yeah.
OK.
And then we're going to massage it into ourinto our meat, mix it well in, try and get into all the cracks and crannies in the meat.
Once the cure is applied, the meat will need to be refrigerated to cure for about seven days.
The first thing you notice is just how much salt is involved in the process.
The salt is obviously not great for us.
It's related to hypertension which is a leading cause of cardiovascular disease.
But it's not just the salt that can cause problems, there's also the sodium nitrite I added which is often used in the curing process.
So, what it is about the sodium nitrite, what does it do? The nitrite, it's very good for the meat, it kills the bacteria in the meat, it stops us getting botulism, however in the stomach environment it's believed that some of that nitrite reacts with amino acids - the building blocks of protein - to form what we call nitrosamines, and we believe that these are quite chemically reactive.
And when they make their way down into the gastro-intestinal tract, they can start interacting with DNA in cells and tissues and that is what we believe initiates the cancer process.
OK, and how strong is the evidence of a direct link between nitrites and cancer? It's a very complicated picture.
Um, we believe that it may contribute but we want to understand why, and this is one potential mechanism.
So nitrites are still only a suspect, we have yet to establish a direct link between them and colorectal cancer.
And nitrites are not the only part of the curing process that researchers wonder about.
There we go, we have liftoff! When meat is smoked, it's often done in massive cold stores, we're doing it on a much more intimate scale.
One of the things that we do to flavour meat is we smoke it, and the same chemicals that we generate when we smoke cigarettes, things called polyaromatic hydrocarbons, are generated in the smoking process.
These chemicals, known as PAHs, stick to the meat - and when we eat it, they can be absorbed by the body.
They can react in a very similar way to the nitrosamines with DNA through our gastrointestinal tract and might be another potential mechanism whereby red and processed meats increase our risk of gastrointestinal cancers.
Like nitrites, PAHs are still only potential suspects when it comes to finding a link between processed meat and cancer.
Still, I'm starting to see why processed meat has such a bad reputation.
But just how bad is bad? The Harvard and EPIC studies both suggest that eating a moderate amount of processed meat increases your annual risk of death by about 20%.
But is this a statistic that's worth worrying about? How does the risk of eating processed meat compare with the risk of doing other everyday things? To untangle the numbers in the studies, I've recruited world renowned Cambridge statistician Professor David Spiegelhalter.
By examining a broad range of stats about who we are and how we live, it's possible to determine how certain things might impact our life span.
As a statistician, you kind of look at numbers, you look at studies and things like that, if you were to kind of nail down what we can really, really say about how long we live, what sort of things are we reasonably certain WILL cut years off your life? Well, the first thing of course is, sadly, being male.
Every male has got the same risk of dying each year as a woman who's four years older than them.
So, on average, men live four years less than women.
Then there's smoking.
We know, for example, that people who smoke 20-a-day have the same annual risk of death as someone who's about eight years older than themselves.
So, on average, over the whole lifetime, if you smoke 20-a-day, it's about eight years off your life.
What about alcohol? Well, I believe the evidence that says the first drink each day is actually medicine, it's going to do you good.
But after that, of course, it's downhill all the way.
And so if you have an extra couple of drinks a day and beyond that, maybe it's about a year off your life.
So, what about the studies that suggest a 20% annual increased risk of death from eating processed meat? Well, let's take two 40-year-old men, who are similar in all ways and one of them has two rashers of bacon every day, say in a bacon sandwich.
Now the bacon-eater would be expected to live two years less.
So roughly you'd expect the 40-year-old who does eat the bacon, on average, to live till he's 78, whereas the one who doesn't, you'd expect him to live till 80.
And losing 2 years over 40 years is pro-rata like losing one hour a day for that bacon sandwich.
OK, that will certainly give me pausepause for thought when I pick up my bacon sandwich.
Eat it slowly.
Eat it slowly and enjoy it as well.
OK.
Yeah.
Wow.
I'm actually quite shaken because if the studies are right and David is right, then that is an incredibly heavy price to pay.
But statistics never convince people to change their mind, it is personal experience, so I'm really keen to discover what effect my heavy-meat diet has been having on my body.
I've been eating about 130 grams of red and processed meat every day for four weeks, that's twice the level that's advised.
Now, I'm only one person and I've only been on the diet for a short amount of time, so the results are going to be specific to me and I'm not reflective of the population as a whole, but that said, I'm obviously very interested to see if it's done anything to my body.
I'm returning to Reading University, where I had a health check before I started my diet.
Nutritional biochemist Dr Gunter Kuhnle studies the impact meat has on the gut.
A simple way of finding out how my gut responded to a high-meat diet is by providing the lucky man with a sample of my faeces.
Dr Kuhnle's team are looking for levels of N-nitroso compounds, compounds that can be formed when we digest red and processed meat and are suspects when it comes to bowel cancer.
What about the effects of my stool samples? We analysed your stool samples and we were quite surprised because we didn't find any change in faecal nitroso compounds.
OK.
So, what we would normally have expected that with this increase in meat, we would have seen an increase in faecal nitroso compounds, and these are the compounds we suspect that are linked are the link between meat and cancer risk and we didn't find anything there.
OK, so something, any explanation again? Well, after we looked at your diet, a possible explanation is that you consume quite a lot of fruit and vegetables - well beyond the five a day - and fibre is known to reduce the formation of these compounds.
Right, so, the fibre, although I was eating a lot more processed meat, I was also eating quite a lot of fibre and that kind of, to some degree, protected me against the changes.
Well, that's quite encouraging I suppose.
Dr Kuhnle has also checked my pre and post-diet blood samples to look at the levels of cholesterol.
Well, your cholesterol went up from 6.
2 to 6.
8, so that's quite a bit of an increase.
Right that is a lot, isn't it? It is.
Not only that, but it was the levels of LDL - the bad cholesterol - that really went up.
Perhaps I'll get better news when I have my body fat checked.
OK, Michael, the news is that your body fat has gone up by three kilos.
Three kilos? Three kilos.
Blimey.
And most of this is in the trunk area, which is not good because this fat is close to the internal organs which means you can become insulin resistant and diabetic.
Indeed, visceral fat and sadly I know all about it.
Not good news, yes.
Three kilos! Putting it simply.
That's absolutely phenomenal.
Yes, yes absolutely.
Right.
Yet more bad news.
There's one last chance for some good news with my blood pressure.
OK, so, Michael, the reading has gone up this time, when you first came to see us it was 118 over 69.
Right, so that was kind of in the good range, wasn't it? It was in theyeah, the really good range on the lower side, now it's 141 over 81.
Blimey.
Which means you have now gone into the high blood pressure range but at the bottom of the high blood pressure range, OK? Blimey, that is high, isn't it? Yes, it is.
Could you say that number again? It's 141 over 141 over 81.
81? Yes.
God, that has shot up, hasn't it? Absolutely.
That is actually quite upsetting.
Yes.
That's right, yes when you think that it's probably due to diet.
I think it's entirely due to the fact I've been on this high-meat diet.
Yes.
I don't think that's done me any good at all.
No.
Well, that was a nasty shock, particularly the effect on my blood pressure and on my cholesterol.
So I'm going to go home now and I'm going to return to my normal diet and I've got to try and get rid of these extra three kilos of abdominal fat.
Tonight, my family and I are having friends around for dinner.
I want to put what I've discovered and digested about meat onto the table.
OK.
When I started making this programme, I didn't think that eating more red and processed meat would have much impact.
So, it was, I must admit, a nasty shock the effect that all that bacon and processed meat I was eating had on my body.
I sort of expected it might have a very small effect but I was actually quite genuinely shocked by how big the effect.
We should probably cut back, particularly discourage the kids from eating quite as much as they do.
Yeah.
Yes, no, I think that's probably right.
There was a point where we were buying I don't know how many packs a week Bacon, yes.
.
.
and they were having it And they were No, quite.
.
.
before every meal and after every meal as they could.
No, quite, there we go.
The pigs can live happy.
THEY LAUGH We all need to make our own decisions.
Me? I'm going to cut right back on the processed stuff - which will make my wife happy.
But I think this kind of red meat, unprocessed and fairly lean is fine on occasion - which will make me happy.
Lovely.
Thank you.
Very helpful.
Lovely, it's very kind of you.
If you are cutting back on meat, perhaps going largely vegetarian or vegan, make sure what you're eating has enough protein, iron, zinc and B12, all the things that red meat has in spades.
And don't replace meat with food high in sugar or refined carbohydrates.
At the moment, the British Heart Foundation recommends that meat can be included as part of a healthy, balanced diet.
I think the problems come when it's not a balanced diet and there's too much emphasis on eating meat and processed meat.
I think what we can be clear for you is that the healthiest diet is a predominantly plant-based diet supplemented with meat.
Roughly per week, how many grams of red meat would you say the average person should eat? I think that the evidence suggests that eating up to, say, 100 grams which is about 4oz every so often is not going to do you any harm.
I think it's much better to kind of vary it.
So I think, you know, a bit of fish here, chicken, a bit of meat there.
I think personally I would I think I'd prefer to eat more vegetables, vegetables, vegetables.
MUSIC: "Little Red Rooster"
Plump sausages, pan-fried and golden brown.
Luscious lamb chops, grilled until pink and tender.
This isn't just ordinary meat.
Depending on what you've recently read or heard on the news, this is either a protein-rich and nutrient-packed dietary necessity MUSIC: "Little Red Rooster" .
.
or an artery-clogging, life-shortening food to avoid.
I am genuinely confused and would dearly love to separate fact from fiction because for many of us, meat is a pleasurable part of our daily diet.
Now as a family, we like meat.
We eat it most days - chicken, lamb, beef, pork and of course, bacon and burgers.
And we're not alone.
Worldwide meat consumption has nearly doubled in the last 50 years.
That's certainly how a burger should look.
That's a very good burger.
Could something that is so ingrained in our culture really be killing us? I'm going to track down the eminent scientists who study the impact of different types of meat.
I want to find out what they've discovered but also what they themselves eat.
Just what is the truth about meat? It's really early in the morning.
It's cold, it's dark and I am off to see more meat than I have EVER seen in my life.
In the last few years, meat has hit the front pages but for all the wrong reasons.
Frankly, I'm sceptical about many of these headlines and want to find out what's behind them.
Does meat really give you cancer? Whoa, right! Oh, that looks like an alien growth! Will eating it shorten your life? Those who consumed higher amounts of red meat had higher risks of total mortality, cardiovascular mortality and cancer mortality.
Is it a killer, or are these claims greatly exaggerated? You're probably looking at about a difference of five years, four to five years in life expectancy.
As well as investigating the latest science, I'm going to put myself on a high-meat diet to see what, if any, effects it has on my body.
This is where a lot of the meat on our tables comes from, a huge meat wholesaler.
Here they prepare up to 30 tonnes of beef, pork and lamb every day.
It gets sent out to butchers and ends up on our dinner plates right across the nation.
That's impressive, impressive speed at which you go.
Blimey.
Does being around all this meat put you off it at all? Definitely not, definitely not.
I've got a very good appetite for meat.
How often? What, do I eat meat? Yeah.
I don't consider it a meal unless it's got meat in it, really.
For people like Pete, in fact for most of us, eating meat is a normal thing to do.
What's more, it has lots of good things in it.
Meat provides some really important nutrients that are essential for health, so mainly protein.
Meat is protein-rich and protein is very important in terms of repair of your body.
And there's also some micro-nutrients such as .
.
iron which is good for helping us to have healthy red blood cells that help to transport oxygen around the body.
Also B12, which is also involved in the working of our blood cells.
B vitamins particularly sometimes can be very difficult to get from a plant-based diet.
And zinc which is important for healthy hair, nails, and also has a role in wound healing and sort of helping us to repair ourselves.
If you don't have meat in your diet, you can certainly still get all the nutrients that you need but you do have to think a little bit more about how you get those.
As a species, we evolved eating meat, though probably not that much or that often.
But how much is too much? Well, to find out you need to do big studies - lots of people followed for many years.
It's those studies that I'm going to look closely at.
Together, they involve almost a million people and for the most part, they're looking at particular types of meat.
There is little evidence that chicken and other white meats pose a health risk so these are off the agenda.
Really, the meats that are under fire are red meat and processed meat.
Now red meat includes beef, lamb, pork, while processed meat could mean salami, bacon, sausages - so those are the meats that I'm going to focus on.
Now I eat relatively modest amounts of meat but would it matter if I ate more? To find out, I'm going to go on a high-meat diet.
I'm going to eat about twice the advised daily amount, something that around 25% of the adult male population in Britain already do.
So let's see what I'll be eating more of.
Red meat is stuff like steak, lamb or pork chops and ground red meat like beef mince, whereas processed meat has been preserved by salting, smoking or by adding preservatives - things like salami, sausages and ham.
On average, Brits eat about 70 grams of red and processed meat every day.
That doesn't include chicken or any other poultry, but about a quarter of British men eat around 130 grams so I'm going to adopt their diet.
Now I think that on average I probably eat 65-70 grams of meat a day, but for the next month I'm going to be going up, nearly doubling it.
So what does 130 grams of meat look like? Well, something like this.
It could be a couple of bits of bacon in the morning for breakfast and a burger in the evening.
That's 130 grams.
Or you simply have a piece of steak about this size or maybe a pork chop this size - that's 130 grams.
Or you might go for one sausage plus a couple of bits of ham for lunch.
And if you're wondering how much that adds up to over the course of four weeks - well, it's about this much.
And frankly that looks quite doable.
To monitor how this seemingly moderate amount of meat affects my body, I've come to the Food and Nutritional Sciences Department at Reading University.
Hello there.
Michael.
Hello.
I'm going to have a health check before and after the diet to see if a bit of extra meat changes anything.
What's happening at the moment is I'm about to have some blood taken so they can measure my cholesterol and they're also going to put me on the weighing machine over there so they can measure things like body fat, weight, things like that.
Oh, yes, felt that one.
And the idea is to get a baseline figure so that before I go on my enhanced meat diet, they've got some figures.
I'll come back here in a few weeks' time, they'll do it all over again and we'll see if the meat has made that much of a difference.
I'm just a sample size of one so the results will be very personal and not representative of everyone.
Desirable ranges should be in the fat percentage between 11 and 22% and you are 15.
3 so you're well within the desirable range.
I'm desirable.
For a rather more scientific way to assess the impact of meat, I've come to Southern California.
Here they've been conducting one of the longest studies ever into the effects of diet and lifestyle on health.
I'm in Loma Linda which is in California near Los Angeles and I'm here to meet the Hucksey family who are part of an unusual group of people.
They're unusual because their religious beliefs seem to contribute to their impressive longevity and general good health.
Hello, good morning, hello.
Very nice to meet you.
Welcome, please come in.
Thank you very much.
Hiya, gang.
This is my family.
Hello.
Wife Danielle.
Hello.
Hello.
The Huckseys are Seventh Day Adventists, a Protestant sect founded in the 1800s.
Even though it's Saturday, we're off to church because that's when Seventh Day Adventists observe the Sabbath.
CHURCH ORGAN PLAYS Now Seventh Day Adventists like the Huckseys live considerably longer than the average American.
CONGREGATION: # Safe within his hand that guides us Hidden in That's probably because they believe that leading a healthy, wholesome lifestyle is what God wants them to do.
In the Bible, in 1st Corinthians 6, there is a verse that talks about our body is the temple of the Holy Spirit and that we should use our bodies for the glory of God, and that we are to take care of our bodies so that we can not only live longer but also be more helpful to other people while we ARE living.
We're sitting down to a different kind of breakfast because their religion encourages vegetarianism.
So can you tell me what I'm looking at here, then? So this is - it looks like scrambled eggs but it's not, is that right? Scrambled tofu.
OK, scrambled tofu, and these, I'm guessing, are not pork sausages? No, those are Saucettes, so another soy-based vegetarian.
OK.
Heavenly Father, thank you for the chance to enjoy the Sabbath day and the food that you've prepared.
Please bless our time together in Jesus' name, amen.
Amen.
The Huckseys are strict vegetarians but because their church only RECOMMENDS a veggie diet, many of the Adventist community eat some meat.
Is it primarily religious, or ethical, or was it health? It was health and I wanted my kids to be healthier.
I think often as parents, you do things for your kids that you wouldn't do normally and I wanted them to be healthier.
And now that I have an eight-year-old, I think I want to live a long time for him and be healthy for him.
You look at products that God has created, such as a grapefruit, whole grains, sweet potato.
The closer you look at them, you realise how beautiful and nutritious they are.
Not only is it showing that Adventists are living seven years longer, but the quality of those elderly years! How long do you expect to live till? My grandmother just passed away at 103.
OK, right! That's impressive! CHURCH BAND PLAYS What makes Adventists of particular interest to scientists is that although half are vegetarian, around half eat meat so the two groups can be compared.
And unlike the wider population, Adventist meat-eaters tend not to be heavy smokers or drinkers, factors which CAN influence any comparisons between vegetarians and more red-blooded Americans.
Since the 1950s, scientists at Loma Linda University have been conducting numerous health studies on Adventists.
The most recent have been trying to identify the health habits of the long-livers.
I am here to meet Dr Gary Fraser who's been leading this research for three decades covering over 150,000 Adventists.
These huge epidemiological studies track people's diets and lifestyles and look for associations between what they eat, their overall health and what eventually kills them.
Hello.
Hi.
Hi, Mike Mosley, hello.
Nice to meet you.
I'm joining the good doctor for lunch and as I'm on a high-meat diet, our choices couldn't be more different.
OK, so differences in what we've got here, then.
I've got pulled pork while Dr Fraser has a vegetarian salad with nuts.
I have to confess, I had bacon for breakfast as well.
OK.
I had four rashers of bacon.
Wow! All right.
I hope you survive this experiment.
Thank you! So kind of broadly, what have your studies revealed? That when you look at cardiovascular risk factors in a broad sense - diabetes, hypertension, being overweight, having increased blood lipid levels - that the vegetarians are doing better than the non-vegetarians.
And indeed that has translated in most of the studies to the vegetarians having a lower risk of heart attack and cardiovascular disease, so that whole area, I think, is fairly well established.
Dr Fraser found that men in the study who ate beef at least three times a week had double the risk of fatal heart disease compared to the vegetarians.
And this apparently massive risk to health was in people eating under 60 grams a day, which is less than your average Brit and half what I'm currently eating.
So you have found that even eating what some people would regard as quite a modest level of meat makes a difference.
Yes.
I mean, how big a difference? You know, I don't think we have all of the answers on that to be very precise about it and of course your plate of food there has got some things on there that go beyond the meat that I wouldn't necessarily recommend.
So let me put it this way.
That plate as compared to this plate, where I have replaced the meat with nuts and with whole-grain bread and so forth, our evidence says that you're probably looking at a difference of five years, four to five years in life expectancy.
The Adventist studies certainly suggest that vegetarians lead longer and healthier lives, and Dr Fraser makes a compelling case for avoiding meat.
So is that the end of the story? Well, no.
For starters, if meat is as bad for you as the Adventist study suggests, what's in it that is doing the harm? Let's take the five most popular meat products in the UK by volume purchased.
They are whole chicken, bacon, pork sausages, pork sliced cooked meats - things like ham and salami - and beef mince.
Since we are concentrating on red and processed meat, I want to compare bacon, pork sausages and beef mince with some vegetarian options, to find what's in the meat that could be damaging our health.
Dr Orla Kennedy is a nutritionist and dietician at Reading University.
She's chosen three popular vegetarian foods commonly eaten instead of meat to do a head-to-head comparison.
We've got vegetarian sausages, we've got tofu, OK, made from soya bean curd and then we've got cheese, good old-fashioned Cheddar cheese.
None of it looks terribly appetising, does it, in a kind of cold state laid out? No, no, not quite.
Maybe the cheese looks the tastiest there right now, definitely.
Well, the tofu - maybe not.
Before I turn to the bad, I want to look at the good.
Let's start off by looking at protein.
What's the protein content of these different foods? Beef mince has the highest amount of protein and it's good high-quality protein.
Not far behind that is the cheese, OK, quite high in protein as well.
Cheese has just over 25 grams of protein per 100 grams, only slightly behind the beef mince.
Vegetarian sausages and ordinary sausages, there's not much difference between them.
Interesting that both the pork and veggie variety contain almost the same amount of protein.
And the tofu is last.
That's going off the pedestal.
What's interesting in terms of the red meat is proteins are made up of amino acids and there are a number of amino acids which are essential which the body can't make but actually meats provide these, so meats are a complete set of proteins, whereas you won't get that in the vegetarian or the kind of tofu alternatives.
What many people probably don't realise is that meat can be richer in micro-nutrients than vegetables, particularly when it comes to some of the less well-known vitamins.
So what about vitamin B12? Now that's one of my favourite vitamins, not terribly well-known vitamin or talked about but associated with brain development.
I like my brain.
So king of the B12s is the beef again.
Surprisingly, actually - cheese is quite high.
It's very close.
You get three micrograms of B12 in every 100 grams of beef mince.
The cheese offers almost as much but the other veggie options tested have absolutely none.
So far, the meat's doing well but how does it fare when it comes to the Lord Voldemort of the diet world? And finally, saturated fat.
Saturated fat.
It's actually the cheese that has the highest amount of saturated fat.
That's over 20 grams of saturated fat per 100 grams of cheese.
That's surprising.
That is surprising.
However, the recommendations in terms of portion sizes are - for cheese it's a lot less, so a typical portion is about 30 grams.
People tend to eat less cheese than they do meat and the other vegetarian foods being tested have hardly any saturated fat, certainly compared to the fat.
Beef mince, the bacon rashers and the pork sausages have almost the same level of fat.
They're all much of a muchness.
And that muchness is a considerable amount of saturated fat.
They all contain around 16 times the amount found in the tofu.
So while meat tends to deliver more nutrients and micro-nutrients, on the whole it also contains more saturated fat.
And it's the high levels of saturated fat you find in red and processed meats that gives them their unhealthy reputation.
The actual reasons why we see an increased risk of coronary heart disease with a higher intake of red meat and processed meat, we don't really know exactly but there are several suggestions as to why that could be.
So firstly it could be the saturated fat content that we see in say fattier red meats and also processed meat.
Saturated fats mainly come from animal sources so animal fats, things like lard, dairy fats, butter.
These are all things that are high in saturated fats.
They're the fats that you get around meat so around your chop, under the skin of chicken and also marbled through steak.
Some red meats tend to have about 50% of the fat comes from saturated fat, and 50% from unsaturated fat.
This is saturated animal fat.
Now unlike vegetable oil, this is fat that is solid at room temperature.
For decades, we've been told that eating saturated fat leads to elevated cholesterol, to heart disease and then eventually to death but it's perhaps not quite as simple as that.
It was back in the 1950s when research in the USA started to show a link between saturated fat and heart disease.
'The chemist heats a sample in an oven 'and pours the fat into a flask.
' At the time, red meat was considered to be a healthy and wholesome part of our diet.
'Prepared meats are easy to serve and good to eat.
'They are enjoyed by almost everyone, everywhere, every day.
' But when the connection between fat and heart trouble was made, red and processed meat were firmly in the firing line.
By 1955, fat had become such a big issue that when President Eisenhower suffered a heart attack, one of the first things his doctors did was put him on a low-fat diet.
Red and processed meat went from something we enjoyed to something that could carry us off to an early grave.
For years, studies continued to reinforce the apparent link between saturated fat and heart disease.
It seemed we would never again eat meat without feeling our arteries groan.
Saturated fat and, by association, fatty meat continued to be the big bad villain well into the 21st century but in the last couple of years new studies have thrown that association into question, suggesting saturated fat might not be quite so bad after all.
One of the most influential people behind this research is a doctor who works in Berkeley, just across the bay from San Francisco.
What he and others discovered has shaken confidence in some of the advice that has been mainstream for decades.
Dr Ronald Krauss is a world expert on diet and health.
Ever since he graduated from medical school, Dr Krauss has been researching the impact that cholesterol and diet have on heart disease.
We're meeting for breakfast and, as I'm still on my special diet, I'm on the hunt for meat, not always as easy as it sounds.
I'm actually looking for bacon.
Do you see the words bacon? Bacon? This is a Jewish deli, so Oh, right, I'm not going to - I'm not going to see bacon here! They might have it.
It's a Jewish deli.
But I wouldn't count on it.
For years, Dr Krauss was an adviser to the American Heart Association and a firm believer that higher saturated fat meant a higher risk of heart disease.
But when he tried lowering people's cholesterol levels by putting them on low-fat diets, he got a nasty surprise.
We thought that everybody would get better on this diet, that their cholesterol profile would improve.
What we found was that the average man, whom we were studying, with a normal profile to start with, actually got worse.
Not surprisingly, this made Dr Krauss question whether saturated fat was quite as bad as everyone believed.
So he re-analysed 21 separate studies that looked at saturated fat and heart disease.
His new analysis found no obvious link.
When I first read your paper, which was a while ago, it was a shock and a revelation at the same time, because, you know, I was also convinced saturated fat must be bad.
Looking at all the studies, on the average, there was no net effect of saturated fat per se on heart disease risk, so heart-attack risk was slightly higher but not significant.
Stroke risk was actually reduced and so overall if you took it across a fair range of disease, heart disease and stroke, there was absolutely zero effect on those conditions.
Others have come to a similar conclusion.
Now that doesn't mean saturated fat is a health tonic but it does suggest the fear of saturated fat has been overdone.
But is there something else in red meat that could be clogging our arteries? So we know that there is an association between high intakes of processed meat, red meat and heart disease but we don't really know why.
Of course the evidence with saturated fats has changed in recent times and so this kind of makes the whole arena much more interesting but a little confusing.
And I think it's very important that we understand the mechanisms before we jump to conclusions about what we do about it.
And so it will be very interesting to see what we learn next about the connection of red meats and cardiovascular diseases.
Dr Krauss is currently involved in new, more controversial, research into meat coming out of the Cleveland Clinic.
It suggests that, yes, there is an ingredient in red meat that could increase your risk of heart attacks but bizarrely, it's concentrated not in the fat but the lean part of the meat.
It's a nutrient called L-carnitine which is abundant in red meat, like the steak Dr Krauss is cooking me for lunch.
Carnitine was really the substance that led to concerns about meat.
It does appear to have effects on the build-up of cholesterol in the cells that form plaque in the arteries.
This research suggests that L-carnitine can react with bacteria in our gut to produce TMAO, a substance that can slow down removal of cholesterol from our arteries.
It just happens that the bugs that live in our intestine seem to like to eat carnitine and they happen to produce this substance and they don't care what happens after that.
So the TMAO, which are the kind of bacteria, have kicked off and are then going to be going into my arteries and they're going to be clinging onto the fat - that's right? That's kind of the hypothesis, that's the theory, is it? That's the hypothesis.
It's still early days but research on animals has shown that feeding them carnitine does lead to clogged arteries.
This is not something that has been proven to occur in our bodies but it's a potential mechanism for how this might work.
Ironically, we now have evidence that saturated fat isn't so bad and that lean meat which we've been advised to eat instead could be doing damage.
The L-carnitine hypothesis is very, very interesting - it certainly gives us another avenue to explore.
But I think what's interesting is that it may not be the obvious offenders as we first thought they were, the saturated fat and the salt.
They might be important for other reasons but it might be this other thing, when we're talking about meats, that is actually the problem.
At the moment, the jury is still out about what it is in meat that can increase your risk of cardiac problems and also how big the risk really is.
So where does that leave me? At this moment in time, pretty confused.
As I tuck into yet another burger as part of my high-meat diet That's how a burger should look, right there.
It's clear that unearthing the truth about meat is far from straightforward.
That's a very good burger.
As well as health, meat is about our culture, who we are.
We have to be clear that there are things above and beyond the health effects of foods that are very important to us.
There is something about its place in our culture, in our society.
It's a sign of affluence to be able to put meat on the table every day.
Meat is also seen as quite a centrepiece to a meal.
So if you think about Christmas or a Sunday roast, you usually have a big piece of meat in the middle of the table so a lot of families bond around that meal.
So far, I've heard from two experts with radically different points of view.
I still don't know how much meat is safe to eat.
And amongst our favourites of beef, pork, mince, sausages, bacon and ham, are some clearly worse than others.
Looking for more answers, I've come to Boston.
At Harvard University's School of Public Health, they've recently completely the world's longest-ever study looking at the health effects of eating different foods.
As part of it, the researchers also looked at red meat and processed meat separately, to assess their relative impact.
The research is the life's work of the man some call the father of nutrition epidemiology, Dr Walter Willett.
So, this is kind of healthy food, yes? Yes, this is I think a very good option of healthy alternatives and the food service here has been really great in terms of trying to offer what we see to be important for health outcomes.
Enjoying the cartoon up there.
Makes you look a little like Colonel Sanders of Kentucky Fried Chicken fame.
No relationship.
Dr Willett and his team have been following the diets of over 100,000 people for over 30 years, another huge study.
The results were clear, starting with those for unprocessed red meat, basically fresh meat like minced beef, steak and chops.
We found in this population of about 120,000 men and women that those who consumed high amounts of red meat had higher risks of total mortality, cardiovascular mortality and cancer mortality.
Right, so they died of heart attacks and they died of some cancers? Yes.
They found eating red meat had a relatively modest impact.
85 grams a day, the size of an average beef burger, was associated with a 13% increased risk of premature death.
Eating processed meat was much worse.
If you had steak, burgers, and then you have kind of bacon and hot dogs over here, which is the worst? Processed meat like bacon and boloney and sausage are ounce-for-ounce several times worse.
In fact, the study suggested that eating about 35 grams of processed meat a day - a couple of rashers of bacon - was associated with a 20% increased risk of premature death.
This was mainly because of an increased risk of heart disease and cancer.
Bad news, considering three of the UK's top five favourites, bacon, pork sausages and ham, all fall into THAT category.
How has your research affected how you eat? I grew up in the Midwest and red meat was part of our diet probably three times a day.
And on most days, we often had it for breakfast in one form or another, sandwiches, hot dogs at school and usually hamburger, meat loaf, something like that at dinner time.
But my diet has changed quite a bit in that way, as we've seen the data come in, that I have red meat maybe a few times a year.
I'm not a strict vegetarian.
A few times a year? A few times a year.
Well, that was actually very disappointing, particularly as I'm on this high-meat diet, because I was hoping for just a few crumbs of comfort but Dr Willett had almost nothing good to say.
Things are looking grim for lovers of burgers, beef and bacon.
But just when I thought things were becoming clearer, I came across another study and its findings don't quite match up with Dr Willett's.
The European Prospective Investigation into Cancer and Nutrition, or EPIC for short, followed even more people than the other studies I've looked into though for a shorter period, 12 years.
When you compare it to the American studies, there's a striking difference in their findings.
Now these are the results of the so-called EPIC study and it really was epic.
The researchers followed half a million people in ten countries for more than 12 years, and their conclusions are very different to the Harvard study.
They found that eating moderate amounts of red meat had no effect on mortality.
In fact, they conclude that "a low - "but not zero - consumption of meat might be beneficial for health.
"This is understandable as meat is an important source of protein, "iron, zinc, B vitamins, vitamin A "and essential fatty acids.
" In other words, eating small amounts of red meat seemed to be better for you than being a vegetarian.
So, the Harvard study found a modest association between moderate red meat consumption and early death, the European study didn't.
The red meat argument is slightly less clear at the moment.
We wouldn't expect two studies to have identical results.
However, in general, when studies have different results, it can be difficult to pinpoint the exact reason for the difference, so we're not as confident that there is a real association between red meat and early death.
And the fact is that observational studies like these can never really prove that specific dietary habits cause a disease.
These types of studies can find associations between dietary components, for example, red meat and disease, but we can't absolutely prove for certain that it is the dietary component that is causing the disease.
In light of the varied results of these long-term studies, just how much red meat do the experts I've met think we should be eating? If one is able and comfortable to have no red meat at all is a good thing.
However, you know the population is not going to become vegetarian.
Um, and so I think one starts with the concept of meatless days.
It looks like having red meat quite infrequently, say once a month, is really an optimal diet.
It's good to think of it as a special event, like, I don't know if you consider here, but in New England, lobster is a special event.
It's not something that we have on an everyday basis.
We think that lean meat in particular is not a hazard to health if it's consumed in moderation.
From the evidence so far, what I conclude is that eating a lot of red meat every day is not a great idea.
But a modest amount a couple of days a week is unlikely to do you much harm.
Now, before meat-eaters go off rejoicing, there is a sting in the tail, because both the EPIC study and the Harvard study found that eating moderate amounts of processed meat, that is, bacon, sausages, salami, did have a significant effect on your risk of getting heart disease and cancer.
So, just how might processed meat cause cancer? Here at St Thomas's Hospital, they see hundreds of patients each year who are suspected of having colorectal and bowel cancer.
It is the third most common cancer in the UK and the one that has the clearest links to a high-meat diet.
Consultant gastroenterologist Dr Jeremy Sanderson uses a colonoscope to check for early signs of bowel cancer.
It's a flexible tube with a camera attached inserted into the rectum and guided around the bowel, giving remarkable high-definition pictures inside the body.
He's keen to show me how the equipment works.
Much to his disappointment, I turn down the opportunity for a personal examination.
This is a standard Olympus colonoscope.
As you can see, it's about a metre and a half long but you'll be pleased to know we don't usually need to use all of that instrument.
OK, how far do you go then normally? Normally, because the bowel is quite flexible, and in some people you can get almost all this telescope coiled up into the bowel if your bowel's very flexible, and that's the art of colonoscopy, is to be able to straighten it, concertina the bowel down.
We sometimes say it ends up at the end of the treatment looking a bit like a question mark shape.
What are you looking for? We're looking for the "polyps" they're called, they're little tiny mole-like growths on the lining of the bowel and steadily what happens over a period of five, ten years, those little growths turn, get bigger, and a bigger polyp, and finally can become a cancer.
This is the view Dr Sanderson gets when he's searching for polyps in the large bowel.
So, what am I looking at, at the moment? Well, essentially thisthis is a normal colonoscopy so you're looking at the lining of the colon, you know, down the end of the instrument.
It's a sort of very high resolution video camera.
How far up, so to speak, are we? We're about 40cm up.
As you can see, the nice normal smooth lining, you can make out blood vessels.
In fact, when the bowel's altered or inflamed, one of the first things that goes is the ability to see the blood vessels in such detail.
The architecture is very strange, isn't it? But things look very different when the patient has an abnormal bowel.
Whoa, right, I had no idea.
That That is a polyp, is it? That is a polyp.
So what you're seeing here, and in fact you can see it's on a stalk Can you see it here? Oh, wow, there you go.
Here's another one.
Oh, that looks like an alien growth.
Yes, it's grown to a size.
And that started It looks huge.
Well, that's about that's about 2cm.
It started as a small, little polyp.
It grew, it grew and it's pulled a bit of the lining with it.
How old would this person be? This person is in their 50s.
You'd come across that and you're going, "That's abnormal.
" If the polyps aren't removed, they can turn cancerous.
Why might a diet rich in meat lead to polyps? Wellas doctors always say, it's complicated.
There are various factors in meat, particularly in processed meats, chemical factors that have been shown to promote cancer or to promote increased growth of cells.
In light of what I've heard from other experts, I'm curious to find out what Dr Sanderson himself eats.
Do you eat red meat? I most certainly do eat red meat.
I believe in being an omnivore.
I don't think I'm an excessive meat eater.
OK, define excessive.
Well, I think I'll have I'll have maybe haveyou know, two bits of red meat each week.
If I was going to make one change to my diet, I think it's the reducing those processed meats that is the one good opportunity and then you can keep your roast beef and yourand your steak.
Dr Sanderson thinks the most effective way to prevent bowel cancer is to have a colonoscopy in your mid-50s, so any polyps can be removed.
What we've done here is we have delivered this snare wire around the polyp and it's sitting on the stalk, and we've tightened it and now you'll see we're going to apply a current to this stalk, and then you'll see some smoke and burning generated.
That's all on the end of the endoscope? Yes, so we're just tightening it and thenthere it goes, and that's it, polyp gone.
It's gone, "pop".
We call that an ex-polyp.
So, what is it that makes processed meat like ham and bacon potentially carcinogenic? What's in it that could promote the growth of cancerous polyps? I'm back at Reading University's Food and Nutritional Sciences Department to find out.
And what better way than to actually make some? Dr Danny Commane is a specialist in gut health and colorectal cancer.
He's gathered together everything we need to turn pork into bacon, the nation's, and my, favourite processed meat.
Hi there.
Hi, Michael, we're going to cure some bacon, I'll give you the gloves.
I've never done this before.
OK, so, we've got some sea salt and we need 12 teaspoons of it.
12?! blimey! OK.
Yeah.
It's only when you make it yourself you realise how much salt there is in it.
Yeah, that's right.
Sugar, how much? So, five teaspoons of sugar, and we've just got curing salt which contains our sodium nitrite.
OK, it's not encouraging, it says, "toxic if not used correctly", and how much of this stuff? I'll be careful with this.
Just one teaspoon.
And then, presumably, you just mix it up, do you? That's right, yeah.
OK.
And then we're going to massage it into ourinto our meat, mix it well in, try and get into all the cracks and crannies in the meat.
Once the cure is applied, the meat will need to be refrigerated to cure for about seven days.
The first thing you notice is just how much salt is involved in the process.
The salt is obviously not great for us.
It's related to hypertension which is a leading cause of cardiovascular disease.
But it's not just the salt that can cause problems, there's also the sodium nitrite I added which is often used in the curing process.
So, what it is about the sodium nitrite, what does it do? The nitrite, it's very good for the meat, it kills the bacteria in the meat, it stops us getting botulism, however in the stomach environment it's believed that some of that nitrite reacts with amino acids - the building blocks of protein - to form what we call nitrosamines, and we believe that these are quite chemically reactive.
And when they make their way down into the gastro-intestinal tract, they can start interacting with DNA in cells and tissues and that is what we believe initiates the cancer process.
OK, and how strong is the evidence of a direct link between nitrites and cancer? It's a very complicated picture.
Um, we believe that it may contribute but we want to understand why, and this is one potential mechanism.
So nitrites are still only a suspect, we have yet to establish a direct link between them and colorectal cancer.
And nitrites are not the only part of the curing process that researchers wonder about.
There we go, we have liftoff! When meat is smoked, it's often done in massive cold stores, we're doing it on a much more intimate scale.
One of the things that we do to flavour meat is we smoke it, and the same chemicals that we generate when we smoke cigarettes, things called polyaromatic hydrocarbons, are generated in the smoking process.
These chemicals, known as PAHs, stick to the meat - and when we eat it, they can be absorbed by the body.
They can react in a very similar way to the nitrosamines with DNA through our gastrointestinal tract and might be another potential mechanism whereby red and processed meats increase our risk of gastrointestinal cancers.
Like nitrites, PAHs are still only potential suspects when it comes to finding a link between processed meat and cancer.
Still, I'm starting to see why processed meat has such a bad reputation.
But just how bad is bad? The Harvard and EPIC studies both suggest that eating a moderate amount of processed meat increases your annual risk of death by about 20%.
But is this a statistic that's worth worrying about? How does the risk of eating processed meat compare with the risk of doing other everyday things? To untangle the numbers in the studies, I've recruited world renowned Cambridge statistician Professor David Spiegelhalter.
By examining a broad range of stats about who we are and how we live, it's possible to determine how certain things might impact our life span.
As a statistician, you kind of look at numbers, you look at studies and things like that, if you were to kind of nail down what we can really, really say about how long we live, what sort of things are we reasonably certain WILL cut years off your life? Well, the first thing of course is, sadly, being male.
Every male has got the same risk of dying each year as a woman who's four years older than them.
So, on average, men live four years less than women.
Then there's smoking.
We know, for example, that people who smoke 20-a-day have the same annual risk of death as someone who's about eight years older than themselves.
So, on average, over the whole lifetime, if you smoke 20-a-day, it's about eight years off your life.
What about alcohol? Well, I believe the evidence that says the first drink each day is actually medicine, it's going to do you good.
But after that, of course, it's downhill all the way.
And so if you have an extra couple of drinks a day and beyond that, maybe it's about a year off your life.
So, what about the studies that suggest a 20% annual increased risk of death from eating processed meat? Well, let's take two 40-year-old men, who are similar in all ways and one of them has two rashers of bacon every day, say in a bacon sandwich.
Now the bacon-eater would be expected to live two years less.
So roughly you'd expect the 40-year-old who does eat the bacon, on average, to live till he's 78, whereas the one who doesn't, you'd expect him to live till 80.
And losing 2 years over 40 years is pro-rata like losing one hour a day for that bacon sandwich.
OK, that will certainly give me pausepause for thought when I pick up my bacon sandwich.
Eat it slowly.
Eat it slowly and enjoy it as well.
OK.
Yeah.
Wow.
I'm actually quite shaken because if the studies are right and David is right, then that is an incredibly heavy price to pay.
But statistics never convince people to change their mind, it is personal experience, so I'm really keen to discover what effect my heavy-meat diet has been having on my body.
I've been eating about 130 grams of red and processed meat every day for four weeks, that's twice the level that's advised.
Now, I'm only one person and I've only been on the diet for a short amount of time, so the results are going to be specific to me and I'm not reflective of the population as a whole, but that said, I'm obviously very interested to see if it's done anything to my body.
I'm returning to Reading University, where I had a health check before I started my diet.
Nutritional biochemist Dr Gunter Kuhnle studies the impact meat has on the gut.
A simple way of finding out how my gut responded to a high-meat diet is by providing the lucky man with a sample of my faeces.
Dr Kuhnle's team are looking for levels of N-nitroso compounds, compounds that can be formed when we digest red and processed meat and are suspects when it comes to bowel cancer.
What about the effects of my stool samples? We analysed your stool samples and we were quite surprised because we didn't find any change in faecal nitroso compounds.
OK.
So, what we would normally have expected that with this increase in meat, we would have seen an increase in faecal nitroso compounds, and these are the compounds we suspect that are linked are the link between meat and cancer risk and we didn't find anything there.
OK, so something, any explanation again? Well, after we looked at your diet, a possible explanation is that you consume quite a lot of fruit and vegetables - well beyond the five a day - and fibre is known to reduce the formation of these compounds.
Right, so, the fibre, although I was eating a lot more processed meat, I was also eating quite a lot of fibre and that kind of, to some degree, protected me against the changes.
Well, that's quite encouraging I suppose.
Dr Kuhnle has also checked my pre and post-diet blood samples to look at the levels of cholesterol.
Well, your cholesterol went up from 6.
2 to 6.
8, so that's quite a bit of an increase.
Right that is a lot, isn't it? It is.
Not only that, but it was the levels of LDL - the bad cholesterol - that really went up.
Perhaps I'll get better news when I have my body fat checked.
OK, Michael, the news is that your body fat has gone up by three kilos.
Three kilos? Three kilos.
Blimey.
And most of this is in the trunk area, which is not good because this fat is close to the internal organs which means you can become insulin resistant and diabetic.
Indeed, visceral fat and sadly I know all about it.
Not good news, yes.
Three kilos! Putting it simply.
That's absolutely phenomenal.
Yes, yes absolutely.
Right.
Yet more bad news.
There's one last chance for some good news with my blood pressure.
OK, so, Michael, the reading has gone up this time, when you first came to see us it was 118 over 69.
Right, so that was kind of in the good range, wasn't it? It was in theyeah, the really good range on the lower side, now it's 141 over 81.
Blimey.
Which means you have now gone into the high blood pressure range but at the bottom of the high blood pressure range, OK? Blimey, that is high, isn't it? Yes, it is.
Could you say that number again? It's 141 over 141 over 81.
81? Yes.
God, that has shot up, hasn't it? Absolutely.
That is actually quite upsetting.
Yes.
That's right, yes when you think that it's probably due to diet.
I think it's entirely due to the fact I've been on this high-meat diet.
Yes.
I don't think that's done me any good at all.
No.
Well, that was a nasty shock, particularly the effect on my blood pressure and on my cholesterol.
So I'm going to go home now and I'm going to return to my normal diet and I've got to try and get rid of these extra three kilos of abdominal fat.
Tonight, my family and I are having friends around for dinner.
I want to put what I've discovered and digested about meat onto the table.
OK.
When I started making this programme, I didn't think that eating more red and processed meat would have much impact.
So, it was, I must admit, a nasty shock the effect that all that bacon and processed meat I was eating had on my body.
I sort of expected it might have a very small effect but I was actually quite genuinely shocked by how big the effect.
We should probably cut back, particularly discourage the kids from eating quite as much as they do.
Yeah.
Yes, no, I think that's probably right.
There was a point where we were buying I don't know how many packs a week Bacon, yes.
.
.
and they were having it And they were No, quite.
.
.
before every meal and after every meal as they could.
No, quite, there we go.
The pigs can live happy.
THEY LAUGH We all need to make our own decisions.
Me? I'm going to cut right back on the processed stuff - which will make my wife happy.
But I think this kind of red meat, unprocessed and fairly lean is fine on occasion - which will make me happy.
Lovely.
Thank you.
Very helpful.
Lovely, it's very kind of you.
If you are cutting back on meat, perhaps going largely vegetarian or vegan, make sure what you're eating has enough protein, iron, zinc and B12, all the things that red meat has in spades.
And don't replace meat with food high in sugar or refined carbohydrates.
At the moment, the British Heart Foundation recommends that meat can be included as part of a healthy, balanced diet.
I think the problems come when it's not a balanced diet and there's too much emphasis on eating meat and processed meat.
I think what we can be clear for you is that the healthiest diet is a predominantly plant-based diet supplemented with meat.
Roughly per week, how many grams of red meat would you say the average person should eat? I think that the evidence suggests that eating up to, say, 100 grams which is about 4oz every so often is not going to do you any harm.
I think it's much better to kind of vary it.
So I think, you know, a bit of fish here, chicken, a bit of meat there.
I think personally I would I think I'd prefer to eat more vegetables, vegetables, vegetables.
MUSIC: "Little Red Rooster"