The Atkins Diet - transcript

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NARRATOR (BARBARA FLYNN): The world’s most beautiful and famous have swallowed his advice. He wrote one of the biggest selling diet books of all time, and it was based on his extraordinary belief that you could eat as much as you desire and still lose weight. His name was Dr Robert Atkins, author of the Atkins new diet revolution. To some Dr Atkins was a hero, to others his diet was scientific heresy and potentially deadly. Tonight in a series of ground breaking experiments Horizon investigates the truth behind the most controversial diet in history. Does the Atkins diet really work and is it dangerous?

NARRATOR: This is Brian, he’d like to look like this, but in reality he looks like this. His lifelong quest to be thinner has taken him through every diet in the book.

BRIAN CLIVAZ: I first started dieting about twenty five years ago and I must have done just about every diet there is. I’ve done the low fat diet. I’ve tried the Carol Vorderman Detox diet. I’ve done the various vegan and vegetarian. The Cabbage Soup diet. I’ve done Montignac. The Swedish Heart Attack Diet, Slim Fast, Boiled Egg diet. There’s a grapefruit based one which is absolutely dreadful. It’s probably better just to go on a fast frankly.

NARRATOR: But today Brian is tucking in to his favourite lunch of roast lamb, followed by two main courses, and he’s not bothered about how many calories he eats. Believe it or not he’s on a new diet. Welcome to the weird world of the Atkins Diet. A world where fat food apparently makes you thin. Where so much we’ve been forbidden to eat is allowed.

BRIAN CLIVAZ: The great thing about Atkins is everything tastes good, everything you can eat is what you want to eat.

NARRATOR: When Brian meets up with his chef it becomes apparent just how strange the diet seems to be.

BRIAN CLIVAZ: We don’t want that, celery.

CHEF: What about nuts?

BRIAN CLIVAZ: Nuts are fine.

CHEF: Clotted cream?

BRIAN CLIVAZ: Clotted cream is excellent.

NARRATOR: Brian has already managed to lose five stone by cutting down on carbohydrates.

BRIAN CLIVAZ: Scones no, pasta out.

CHEF: Oh, pasta gone.

BRIAN CLIVAZ: Potatoes, no, get rid of them.

CHEF: Alright they’re gone, they’re gone.

BRIAN CLIVAZ: They’re gone. Mushrooms are fine.

CHEF: What about bread?

BRIAN CLIVAZ: Bread, you can chuck all them away.

CHEF: Oh no, no.

BRIAN CLIVAZ: Butter, you can cook….

NARRATOR: Even the amount of healthy fruit is restricted.

BRIAN CLIVAZ: No bananas, we’ll lose bananas. Shouldn’t really have melon or pineapple.

BRIAN CLIVAZ: I started Atkins nine months ago, and when I started I put this piece of string around my waist, to, so I could keep a record of it. And it goes all the way round and so far you can see I’ve lost that oops, I’ve lost that much. Which is about ten inches.

BRIAN CLIVAZ: Sausages, yeah they’re great and bacon will do, bacon is good. Lobster, fish, scallops, crab is great.

NARRATOR: By sticking to food high in protein and fat, Brian hopes to lose another stone in the next four weeks.

CHEF: There’s a lovely bit of fillet for you.

BRIAN CLIVAZ: Yeah fillets for my dinner, you can chop me off a nice large chunk please.

CHEF: A big steak.

BRIAN CLIVAZ: A big steak with a lot of béarnaise sauce.

BRIAN CLIVAZ: And if I lose another eight inches I’ll be at the maximum end of the Marks and Spencer range of trousers. NARRATOR: Without the faintest regard for calories Brian confidently sets about eating himself thinner. And he has one small orange book to thank. The Atkins new diet revolution is a phenomenon. Over seventeen million people worldwide have been captivated, making it one of the biggest selling diet books in history. Its author was hailed as the new messiah of thinness. But forty years ago he was just an overweight cardiologist. His name was Robert Atkins.

JAQUELINE EBERSTEIN: Bob loved food, he probably had at least more than one chin and at that age he shouldn’t have had more than one chin. Bob is someone who has absolutely no discipline and never wanted to be hungry. So he was really hunting around on ways to try and deal with his weight.

NARRATOR: Worried about his weight problem Dr Atkins began searching through some medical magazines. He came across something that would change the course of his life.

JAQUELINE EBERSTEIN: He found an article about a diet that he had not heard of before. And it appealed to him because it was different and he’d already tried low calorie which he didn’t like and so he thought he would try it and see if this worked.

NARRATOR: The diet almost eliminated carbohydrates, starchy foods like pasta and bread, and even some fruit and vegetables. Almost anything with sugar was forbidden. But the diet said yes to all protein, meat, fish, eggs, and to all the fats they contain. And yes to other fats like oils and lards.

JAQUELINE EBERSTEIN: He had wonderful success, he lost weight quickly, he felt good, his clothes got looser and he thought he’d really found something he could live with. So because it worked so well for him he decided he was going to start to try it on some patients that were also overweight.

NARRATOR: And it worked, the results were stunning. Dr Atkins patients lost weight quickly and easily. He began to realise there was something very special about this diet. It seemed you could eat as much as you want as often as you want and still lose weight. There appeared to be no need to worry about calories. This was the heart of the Atkins diet mystery. How could people eat lots of food without counting calories and become thin? But this extraordinary idea would leave Dr Atkins in to serious trouble. The Atkins diet challenged nothing less than the most fundamental law of the universe. There is a law in science that says energy can neither be created nor destroyed. It is so important it underpins the workings of everything in the cosmos. It is the first law of thermodynamics.

Prof JOE MILWARD: The first law of thermodynamics is the foundation stone of our understanding of chemistry and physics. In the universe there is a finite amount of, of energy. It, it can not disappear and it can not be created from nothing.

NARRATOR: and amongst all the forms of energy in the universe one is food. We measure this energy as calories. This fairy cake is pure energy. It’s packed with a hundred and twenty calories. Add oxygen to speed up the process and this demonstration reveals just what a hundred calories really mean.

Prof JOE MILWARD: That’s a lot of energy coming out. That’s a lot of calories. And those calories are liberated in the body. They can’t disappear, they either fuel metabolism or they finish up on your hips as fat.

NARRATOR: This was the central problem with the Atkins diet. Science said that nowhere in the universe can calories go missing. But Dr Atkins seemed to claim that on his diet they could. He said that by cutting carbohydrates you could eat as many calories as you wanted and lose weight.

Prof JOE MILWARD: The central tenet that calories can go missing is a scientific heresy because it does contravene the first law of thermodynamics.

NARRATOR: And if this scientific heresy wasn’t bad enough the Atkins diet seemed to do something even worse. Many scientists were convinced it was deadly. And this was the killer, fat. Scientists believed fat could clog your arteries and was a major cause of heart disease. In the nineteen seventies the rate of deaths from heart attacks was serious and everyone thought that fat was to blame. So advice came from on high, governments all over the world said there was only one safe way to live, to go on a new diet, one that was low in fat and low in calories. This became the doctrine of healthy living. But the Atkins diet seemed to contradict the accepted wisdom of medical science. A diet that allowed you to eat all the fat and as many calories as you wanted just had to be a death sentence.

Dr THEODORE VANITALLIE: In science you're not supposed to get angry but why is someone recommending something that most of us know to be potentially harmful.

NARRATOR: Not only did the Atkins diet seem like a heart attack diet, there was little scientific evidence to back it up.

Dr THEODORE VANITALLIE: The problem with the Atkins diet is that it doesn’t grow out of scientific research. Atkins was out of his speciality, he’s a, he was a cardiologist and not an expert in nutrition.

NARRATOR: Dr Van Itoli and his colleagues at the American Medical Association wrote a damning report. They warned that the Atkins diet was biochemically incorrect and dangerous. The scientific community cast Dr Atkins and his diet out in to the wilderness. And there it might have ended, but over the next thirty years something odd happened. Despite the low fat, low calorie advice, the world got fatter and fatter. Meanwhile people on the Atkins diet seemed to be getting thinner and thinner. The mystery surrounding the diet was deepening. Could a diet that science claimed made no sense actually be working? The first hints to what was really going on had come from a new generation of doctors. Eric Westman from Duke University, Gary Foster from Pennsylvania University. Both used low calorie, low fat, to help people lose weight. Both were concerned by the growing popularity of the Atkins diet.

Dr GARY FOSTER: There was a course of questions about what is the safety and ethicacy of the Atkins diet, and we just didn’t have any data to answer that question.

NARRATOR: Westman’s patients had reported remarkable results on the Atkins diet.

Dr ERIC WESTMAN: Several of my patients did the diet against my wishes and clearly had a lot of weight loss. We know that you have to reduce calories to lose weight and yet it said nothing about calories in the book. How could this possibly work?

NARRATOR: Faced with this contradiction Foster and Westman decided science had to face Dr Atkins head on. It was time to put the diet to the test. Westman went back to basics. Surely a diet that professed you could eat limitless food would make you fat not thin? So he decided to look in to Dr Atkins’s claim that you really did lose weight. A hundred and twenty dieters were recruited. Half were put on strict low calorie. The other half were put on the Atkins diet and told to eat as much as they wanted.

Dr ERIC WESTMAN: We didn’t expect that the diet would do very well. We weren’t really expecting to find much weight loss at all. It was also a very extreme diet so that we thought people would have difficulty staying on it.

NARRATOR: After six months of research the results were ready. They were not what Dr Westman was expecting. The Atkins dieters had indeed lost weight.

Dr ERIC WESTMAN: Even though you say nothing about calories, in fact you say you can eat as many calories as you want, people lost weight on the Atkins diet.

NARRATOR: And they hadn’t just lost a few pounds, they’d lost twice as much as those on the low calorie diet. Not only did the Atkins diet actually work it was the hands down winner. It seemed you really could get thin without worrying about calories. But there remained the other unresolved issue. The scientists’ biggest criticism of the diet was that the high fat would lead to high cholesterol which would clog the arteries and kill. Back in Pennsylvania Gary Foster embarked on a study to find out if the Atkins diet really did increase the risk of heart attack.

Dr GARY FOSTER: We fully expected that this would be a quick and dirty study. We would show that cholesterol would actually get much worse. It would be the first and last study of the Atkins diet.

NARRATOR: But when Foster sifted through the data he too couldn’t believe his eyes.

Dr GARY FOSTER: My first reaction was could this be, this doesn’t make a lot of sense. Not only were there no bad effects of the diet in terms of cholesterol, but actually there were quite positive ones.

NARRATOR: In other words despite the fears about eating lots of fat it looked as if the Atkins diet might not be bad for the heart after all.

Dr GARY FOSTER: You actually had about a tenfold improvement in cholesterol compared to a low fat, low calories diet.

NARRATOR: For some strange reason it appeared the Atkins diet might benefit your health. It seemed Dr Atkins could have been right all along. The medical establishments damning of the Atkins diet appeared unfounded. Studies have now shown that it definitely worked and that it might not be bad for the heart. After the years of doubt and criticism science now had to eat humble pie.

Dr ERIC WESTMAN: It makes you wonder why we hadn’t considered this before. And there is probably some arrogance to think that nobody had listened to Dr Atkins.

NARRATOR: But for all this apparent triumph there was still one huge hurdle between Dr Atkins and mainstream acceptance. The Atkins diet still seemed like scientific heresy. Calories could not evaporate in to thin air. To be accepted Dr Atkins would have to explain how you could lose weight while eating as much as you liked. He needed a credible answer to where the excess calories were going. So he came up with an idea. He said it was all down to how our bodies used food as fuel. The food we eat gets broken down to energy through various chemical reactions. What Dr Atkins realised is that fats, proteins and carbohydrates are converted to energy in very different ways. Mary Vernon is a doctor who prescribes the Atkins diet to patients. She like Dr Atkins believes the answer to where the calories are going can be found in how foods are broken down by the body.

Dr MARY VERNON: Breaking down carbohydrates is one of the simpler set of reactions in your body.

NARRATOR: Carbohydrates are turned to energy in a few easy chemical reactions. It’s as simple as riding a horse from A to B.

Dr MARY VERNON: It’s straight, it’s simple, not much energy has to be expended to get the job done.

NARRATOR: But turning fats and proteins to energy is a much more complicated chemical process.

Dr MARY VERNON: Glycerol changes to dyahydroxiacetone phosphate, changes to glyceraldehyde threephospate, either of those can change…

NARRATOR: At every single reacting energy is lost as heat.

Dr MARY VERNON: …to glucosesixphosphate.

NARRATOR: Dr Atkins’s theory was that by turning fats and proteins in to energy your body already has to work harder. So calories quickly get used up.

Dr MARY VERNON: You wouldn’t have to increase your exercise at all because your body would be working harder so that you could literally sit in your armchair and lose weight.

NARRATOR: In other words you could get slim while doing next to nothing, provided you ate the right sorts of food. And Dr Atkins had another theory about where the calories might go. This one linked to the diet’s most notorious side effect. Atkins dieter Brian has had little to no carbohydrates for twenty days. He’s checking for what’s known in some circles as Atkins breath. Many of the diets devotees complain of smelly breath. But the good news, according to Dr Atkins, is that it means the body has started the maximum fat burning phase of his diet. And a process called ketosis. Dr Atkins claimed ketosis was as delightful as sunshine and sex.

BRIAN CLIVAZ: I don't think you feel very much different when you're in ketosis. I don’t think Dr Atkins had much sex if he thinks that ketosis is better than sex, it’s certainly not.

NARRATOR: Ketosis is what happens when you’ve used up all your glucose stores. Your body has to turn to fat for fuel, hopefully drawing on your fat reserves. As your body burns fats it creates as a by-product molecules called ketones. A few of these ketones escape on the breath giving you that unfortunate side effect. Others escape in the urine. So to find out whether Brian really is in ketosis he’s testing his urine for ketones.

BRIAN CLIVAZ: Mm it’s changed colour, ooh very exciting, let’s have a look. I’ve gone to trace, so there is a trace of ketones there, it’s not very much, probably because I had those glasses of wine on Sunday, very good, so I am in ketosis.

NARRATOR: What Dr Atkins argued is that ketosis was another reason why his dieters could eat to their hearts content. Ketones are in fact calories, and you could literally flush them unused down the toilet.

BRIAN CLIVAZ: Certainly it feels good to be peeing out calories, even if it’s only a small trace. But nevertheless it all helps doesn’t it? Very good.

NARRATOR: It was all coming together. Dr Atkins now had two untested but possible theories to how you could eat more yet still lose weight. It seemed his diet didn’t violate the first law of thermodynamics. Calories were heading down the U-bend and were being used up by breaking down the fats and proteins. The diet’s popularity soared. The book knocked Harry Potter off the best seller list. Meat sales boomed. Bread sales slumped. Papers pleaded with Brits to save our spuds. It seemed Dr Atkins had found the answer.

LARRY KING: The world’s most controversial diet guru Dr Robert Atkins is next on Larry King live.

LARRY KING: Do you have a feeling of I told you so?

DR ROBERT ATKINS: Sure, I’ve had that feeling all along.

NARRATOR: Dr Atkins appeared vindicated. But he was about to be challenged again. Medical science hit back, there was a series of worrying studies. Some researchers suggested eating lots of meat could harm the kidneys. Other scientists found that too much fat may result in breast cancer. Others pointed out high protein diets could be bad for the bones. And there was even a suggestion that one girl had died because of the Atkins diet.

Dr PAUL ROBINSON: What will happen if people stay on this diet for twenty years, will there be an increase in kidney stones? Will there be an increase in colon cancer because of the loss of fibre in the diet? These are questions no one knows the answer to. And so we’ve embarked on this huge societal experiment on this diet and sadly we may find out some because negative answers in the next twenty years.

NARRATOR: The Atkins camp disputes all these complications. With no long term studies focussed on the diet none can be proven. But beyond all that there was still one serious unanswered question. No one had yet systematically looked at how the Atkins diet actually worked. So late last year Horizon commissioned a scientific investigation in to whether Dr Atkins’s theories of how calories are lost on his diet were real or just wishful thinking. The study took place at Kansas University. Somewhere on this sprawling campus a man was locked inside a tiny room. He was there for a whole day and night. His identical twin was subjected to the same treatment. They had both donated their bodies to one of the first attempts to find evidence that you really do lose more calories than normal on the Atkins diet. The team behind this unique study was headed by Joe Donnelly.

Prof JOSEPH DONNELLY: The concept is very interesting, it’s very controversial, in science it’s very nice to be there. It’s nice to do something that isn’t boring, there are millions of people interested in Atkins, really right, wrong or indifferent. So we’re very interested and eager to see the results.

NARRATOR: For two weeks one of the twins was put on the high fat, high protein Atkins diet. While the other was put on the conventional low fat diet. They were then locked inside this sealed chamber. By measuring how much oxygen they breathed in and out the computers could calculate how quickly their bodies were burning fuel. The hope was that this would begin to answer whether more calories are worked off on the Atkins diet by breaking down fats and proteins. Donnelly also tested Dr Atkins’s theory of calories lost as ketones down the toilet. The twins had to donate their bodily fluids for the duration of their internment.

Prof JOSEPH DONNELLY: We’ve collected a litre and a half of urine at each collection period. They’ll be analysed for urinary ketones and then we will know how many calories are lost in the urine. NARRATOR: If Dr Atkins’s theories were right the twin on the Atkins diet should be losing significantly more calories than the twin on low fat. In the morning the twins were released and the results were in. To prove you burn off significantly more calories breaking down the Atkins diet researchers expected the twin on Atkins to have lost at least a hundred calories more than the twin on low fat. And the Atkins dieter did lose some more calories this way, but a total of just twenty two.

Prof JOSEPH DONNELLY: Twenty two calories is too small to suggest that there really is anything going on.

NARRATOR: In other words burning fats and proteins appeared to take up hardly any more energy than burning carbohydrates. It seemed Dr Atkins’s theory that you lose calories when breaking down his diet might be wrong. Next the researchers looked to see whether any calories were lost as ketones in the urine. The twin on the Atkins diet had lost less than a single calorie more than his brother on low fat.

Prof JOSEPH DONNELLY: This is not enough to suggest that this particular demonstration showed a difference.

NARRATOR: It seemed being in ketosis made barely any difference at all. Again Dr Atkins’s theory appeared to be wrong. This came as little surprise to Donnelly.

Prof JOSEPH DONNELLY: I think the results are what we expected. There’s no difference between the two diets.

NARRATOR: The research is at a very early stage, and not all studies agree. But in Donnelly’s first examination of how the Atkins diet works proof of Dr Atkins’s theories remains elusive. This leaves a mystery at the heart of the Atkins debate. People shed weight on this apparently limitless calorie diet. If calories aren’t lost through ketosis or breaking down food what is happening to them? Clues to the likely answer came from the world’s largest dieting study that took place in Britain last year.

JUDGE: Few have confessed to the charge of being overweight.

NARRATOR: Behind the scenes of a popular television series a groundbreaking study put four famous diets on trial. Only now are the full results of that study emerging. Horizon is the first to reveal this research. Three of the diets were conventional low fat, low calories diets. Weight Watchers, Slim-Fast and Rosemary Conley. The fourth was of course the Atkins diet. One of the most important parts of the study was that the dieters kept detailed diaries of what they ate. Only now have these diaries been examined. Joe Milward is an expert in nutrition and was in charge of analysing the data.

Prof JOE MILWARD: We had four groups with sixty in each, so that’s two hundred and forty people. And we had planned to do three diaries. So that’s more than six hundred diaries all together.

NARRATOR: All four diets performed similarly when it came to weight loss.

WOMAN BEING WEIGHED: Yes, yes,

WOMAN BEING WEIGHED: Wow.

NARRATOR: There was no mystery why the low fat, low calorie dieters were losing weight.

WOMAN BEING WEIGHED: Yes.

NARRATOR: They were eating fewer calories than normal. The puzzle was why was the Atkins diet just as effective? But when the researchers turned their attention to the Atkins diet diaries something intriguing began to emerge. The diaries showed that even though they could eat as much as they liked they were actually eating as few calories as the low calorie dieters.

Prof JOE MILWARD: They were losing weight because they were eating less calories. In exactly the same way as those going to the slimming clubs on their low fat diets were losing weight because they had reduced their calorie intakes. It was a simple matter of if you eat fewer calories you lose weight.

NARRATOR: So for all the talk of limitless calories the diaries actually showed the Atkins dieters were eating less than they would normally. For scientists this poses a whole new mystery. Why on earth should people who are allowed to eat all the calories they want choose not to? The suggestion is that the Atkins diet must influence one of our most fundamental instincts, appetite.

Dr SUSAN JEBB: Appetite’s the sort of biological drive to eat. And it’s tremendously important because you know without eating appropriate and sufficient food we clearly can't survive or function effectively.

NARRATOR: Appetite is now at the centre of modern obesity research.

Dr SUSAN JEBB: The hunger drive is incredibly powerful. You only need to feel slightly peckish and you go off in search of something to eat to fulfil that basic biological drive to eat.

NARRATOR: The problem scientists have discovered is that when we start eating we find it hard to stop.

Dr SUSAN JEBB: We’re all very familiar with the sensation of thinking you feel full at the end of the main course, but then desert arrives or the cheese board and maybe you could just manage a little bit more.

NARRATOR: In other worlds scientists think that we are fatter because our appetite drives us to eat too much. So science is looking for a way to kill hunger. And what is intriguing is that the Atkins diet might do exactly that. Ten months ago when Brian began the Atkins diet he weighed twenty three stone.

BRIAN CLIVAZ: Moment of truth. That’s seventeen stone exactly, that’s fantastic. So I’ve lost a stone in a month, about three pounds a week, which is great.

NARRATOR: Dr Atkins had noticed that people on his diet seemed to regain control of their appetite, in other words they felt fuller. And Brian for one notices the effect.

BRIAN CLIVAZ: Strangely on Atkins I feel much less hungry than on any other diet. I think the foods that you're allowed to eat on it seems to satisfy me and I don't have any problems with hunger really at all.

NARRATOR: This may be the secret to the Atkins diet. It works by controlling appetite. But what is it about the diet that kills hunger? Dr Atkins believed that it was due to cutting carbohydrates, but as yet evidence for this theory is so far inconclusive. There may be another reason. The Atkins diet is famous for its fat. Dr Atkins said you could eat as much of it as you like. Is it possible that fat could be suppressing appetite? To find out Susan Jebb and her team decided to run an experiment. All the meals in the study looked exactly the same, but there was a big difference. Half the food had liberal quantities of fat secretly added to it.

Dr SUSAN JEBB: We used things like spaghetti bolognaise or mousses so that you could because easily disguise the fat content of the food.

NARRATOR: None of the volunteers knew which type of food they were getting. But half of them were eating low fat meals, and half were eating high fat meals.

Dr SUSAN JEBB: What we told them is they could eat as much or as little as they wanted and they simply just had to ask when they wanted more food.

NARRATOR: If fat was the magic ingredient that switches appetite off, then the men eating the high fat food would fewer calories than normal to feel full. After four hundred and eighty six meals the results were clear. The fat was having the exact opposite effect. The men on the high fat food needed more calories to satisfy their appetite. They were actually overeating.

Dr SUSAN JEBB: What we conclude from that is that fat doesn’t make people feel full. It doesn’t trigger the sense of fullness and satiety that we believe is fundamental to appetite control.

NARRATOR: So fat wasn’t the reason for the Atkins diet success. This just added to the mystery. There had to be another to explain why the Atkins diet made people eat less. The answer may have come from Denmark. This supermarket in Copenhagen is like no other in the world. It was built by Arne Astrup, a professor in human nutrition.

Prof ARNE ASTRUP: All the food items have a bar code on it, not for, not for pricing but for all the nutrition information with the calories, protein and carbohydrate.

NARRATOR: In this supermarket the check out assistant’s not all she seems. She’s a scientist, and everything in the shop is free.

Prof ARNE ASTRUP: When we announced actually in the television our University here was bombarded and the switchboard broke totally down and there were almost a thousand people who wanted to participate.

NARRATOR: Professor Astrup was running a study to discover the secret of appetite control. To do this he chose sixty shoppers and split them in to two groups. One group shopped for high carbohydrate food, the other group shopped for food high in protein, similar to the Atkins diet but low in fat.

Prof ARNE ASTRUP: One group should eat a lot of, of lean meat from shell fish, fish, poultry and lean meat, and dairy products. And the other group should eat a lot of bread, pasta, rice, fruit and vegetables.

NARRATOR: Both groups were told they could eat as much as they wanted. They should eat to satisfy their appetite just as Dr Atkins advised on his diet. The study ran for a whole year and the results were spectacular.

Prof ARNE ASTRUP: One of the groups was losing much more than the other group. I say it was four or five kilo more.

NARRATOR: When they looked more closely it was clear which group had lost so much weight. it was the group eating a diet high in protein. And the shopping lists revealed why.

Prof ARNE ASTRUP: We could see from the data that the reason why the high protein group had lost more weight was because they had actually consumed fewer calories throughout the study, despite the fact that they had just as the same free access to all the foods they really want to, to eat.

NARRATOR: At last the mystery of how the Atkins diet works may have been solved. It might have nothing to do with calories being lost. Probably nothing to do with ketosis. And apparently nothing to do with burning more calories. Neither does it seem to be due to gorging on fats. The secret to the diets success may be down to something completely different. Protein makes you feel full. Increasing the amount of protein in the diet may control appetite and make people eat less than they would normally. If this research goes on to be confirmed it will be a major advance for science.

Dr ERIC WESTMAN: The idea that you can eat certain foods and that it suppresses your appetite is a breakthrough, this is, this is huge.

Dr SUSAN JEBB: What’s absolutely true is that people who consume large amounts of protein seem to feel fuller quicker than people who consume similar amounts of calories as fat.

Dr ERIC WESTMAN: There’s some chemical change that’s going on there, we just don’t understand, but it’s going to be very important to learn this.

NARRATOR: Sadly it’s not clear how much of this Dr Atkins himself was aware of. On the 8th April 2003 he tripped and fell on an icy New York pavement and hit his head. Nine days later he died. At the time of his death it was starting to become clear how the diet might work, but Dr Atkins may never have realised the extent to which protein controls appetite. However even though it is now clear that the diet can help you lose weight the jury is still out on how it affects your health.

Dr Paul Robinson: I would not go on the Atkins diet until further studies have been done. And I would also not go on it because of the, my concerns about the physiology of the diet.

Dr SUSAN JEBB: We simply don’t have any evidence of the long term health impact of diets which are high in protein and low in carbohydrate.

NARRATOR: It will take science years to understand the full impact that the Atkins diet has on the human body, for better or for worse.