How we should tackle the obesity epidemic

In a study of formerly obese people, researchers at the University of Florida found that virtually all said that they would rather be blind, deaf or have a leg amputated than be obese again. That is the extent of our desire to be slim. Yet two thirds of people in the UK, USA, and Australia are overweight and a quarter obese. Why?

To be slim, to achieve the thing we want more than our sight, hearing, or mobility, we are told that we just need to ‘eat less and do more’. The British Dietetic Association’s advice is “One pound of fat contains 3,500 calories, so to lose 1lb a week you need a deficit of 500 calories a day.

So, why don’t we just follow the advice? Why on earth do we have an obesity problem, let alone an epidemic, when we so desperately want to be slim? I set out to answer that question in the late 1980s. This article is a summary of my findings.


The starting point for understanding the obesity epidemic is the question: what changed in the late 1970s and early 1980s? Was there one thing that happened that could explain the sudden and dramatic increase in obesity? In 1972, World Health Organisation statistics recorded that 2.7 per cent of UK men and women were obese. Fewer than three decades later, in 1999, the same statistics found 22.6 per cent of men and 25.8 per cent of women were obese. Two thirds of UK citizens are now overweight or obese. The USA started from a slightly higher base and displayed a virtually identical trend, with 70 per cent of today’s Americans either overweight or obese.

Yes there was. In 1977 the USA changed its public health diet advice. In 1983 the UK followed suit. A more accurate description would be that we did a complete U-turn in our diet advice from ‘starchy foods are fattening’ to ‘base your meals on starchy foods’. Obesity has increased up to ten fold since – coincidence or cause?

In the 1970s, the fact that fewer than six people in one thousand were dying from heart disease was of great concern to America. American public health advisors wanted a solution. During the 1950s the American scientist Ancel Keys attempted to prove that cholesterol consumption was the cause of heart disease. He failed and he acknowledged this. He then tried to prove that saturated fat consumption causes heart disease, despite this having no logic, not least because saturated fat and cholesterol are found in the same foods.

At the time that Senator McGovern was looking for the first Dietary Goals for the United States, Keys’ theory was not the only idea available for consideration, but it was the best promoted. The rest, as they say, is history.

The USA changed its dietary advice and the UK followed. We told people that fat was bad and carbohydrate was good, not because we knew either fat to be bad or carbohydrate to be good. At the time we changed our advice, the only ‘evidence’ for fat being bad was a feeble suggestion that, in seven handpicked countries, heart disease tended to be related to cholesterol levels, which tended to be related to saturated fat intake. The inference was that heart disease tended to be related to saturated fat, although cholesterol intake was not intrinsically related.

The association was never proven. We had no evidence that carbohydrate was good – just the admission that, if we tell people not to eat fat they must eat something. As the National Advisory Committee on Nutrition Education’s paper Proposals for nutritional guidelines for health education in Britain put it in 1983:

“The previous nutritional advice in the UK to limit the intake of all carbohydrates as a means of weight control now runs counter to current thinking and contrary to the present proposals for a nutrition education policy for the population as a whole… The problem then becomes one of achieving both a reduction in fat intake to 30 per cent of total energy and a fall in saturated fatty acid intake to 10 per cent.”

So started the obesity epidemic. There have been no trials to attempt to justify the replacing of fat with starch in our diet, as the following authorities testify:

  • “There has been no controlled clinical trial of the effect of decreasing dietary intake of saturated fatty acids on the incidence of coronary heart disease nor is it likely that such a trial will be undertaken.” (Committee on Medical Aspects of Food Policy, Diet and Cardiovascular Disease: Report of the Panel on Diet in Relation to Cardiovascular Disease, 1984).
  • “It has been accepted by experienced coronary disease researchers that the perfect controlled dietary trial for prevention of coronary heart disease has not yet been done and we are unlikely ever to see it done.” (Stewart Truswell, ‘Review of dietary intervention studies: effect on coronary events and on total mortality’, Australian New Zealand Journal of Medicine, 1994).
  • “The ideal controlled dietary trial for prevention of heart disease has not yet been done and it is unlikely ever to be done.” (Letter from the Food Standards Agency to Zoë Harcombe, 25 September 2009).

Without undertaking the definitive study, we have nonetheless tried to post rationalise the U-turn in dietary advice. We claim that saturated fat directly causes heart disease. We claim that saturated fat causes heart disease through cholesterol. We claim that saturated fat is trying to kill us and unsaturated fat is trying to save us. We claim that a magic ratio of polyunsaturated fat to saturated fat will save us, despite the fact that it is unachievable with a natural diet. We claim that there is such a thing as bad and good cholesterol and that the former is trying to kill us and the latter is trying to save us.

Finally, we claim that food we have been eating for thousands of years will kill us and modern-man-made-spreads will save us. We have claimed some quite extraordinary things since Ancel Keys’ Seven Countries Study and we have no more evidence now than we had then. We still have no consistent association, let alone got anywhere near proven causation.

As for the possible benefit of carbohydrate, we have not even bothered to post rationalise this. To do so would be pointless – we have decided that fat is bad, so we must eat carbohydrate, so it could only be unhelpful to find anything wrong with carbohydrate.

The crucial change which took place in the late 1970s in America and in the early 1980s in Britain was the increase in fructose sugar used in the manufacture of processed carbohydrate foods. This was due to its cheapness and relative abundance in maize crops. As Dr Robert Lustig, of the University of California, put it in his 2009 article ‘The Fructose Epidemic’ (The Bariatrician, the American Journal of Bariatric Medicine):

“Fructose consumption (as both high fructose corn syrup and sucrose) has increased coincidentally with the worldwide epidemics of obesity and metabolic syndrome. Fructose is a primary contributor to human disease as it is metabolised in the liver differently to glucose, and is more akin to that of ethanol. When consumed in large amounts, fructose promotes the same dose-dependent toxic effects as ethanol, promoting hypertension, hepatic and skeletal muscle insulin resistance, dyslipidemia and fatty liver disease… Fructose from any source should be regarded as ‘alcohol without the buzz’. Obesity prevention and treatment is ineffective in the face of the current ‘fructose glut’ in our food supply. We must learn from our experiences with ethanol and nicotine that regulation of the food industry, along with individual and societal education, will be necessary to combat this fructose epidemic.”

Lustig charts an inexorable rise in fructose consumption across the Western world. Prior to 1900 Americans consumed approximately 15 grams a day, mainly from fruit and vegetables. By World War II this had increased to 24 grams per day. By 1977 it was 37 grams a day; by 1994 55 grams a day; and by 2009, when he published his article, 73 grams a day. Now it was being mainly consumed in fizzy drinks, and processed biscuits, cakes and pastries, and especially by children.

We have forgotten that we eat for nourishment. We have a vital need for nutrition and we have lost this basic value in our dietary advice. If we had stayed true to the principle of why we eat, the most nutritious foods would be evidential in any analysis of fat, protein, vitamins and minerals. They are the liver, sardines, milk, eggs and greens favoured by our elders and not the fortified cereals and margarines favoured by conglomerates and, reprehensibly, far too many dietary advisors alongside.

An industry originated marketing campaign, five-a-day, has become the leading public health message in tens of countries across three continents. It is spoken of as if there is overwhelming evidence behind it, when the reality is that there is none. Worse, if the proponents of pick-a-number-a-day knew what Dr Richard Johnson, author of The Fat Switch knows, they would surely revise their opinion of fructose and never mention fruit juice again. As Johnson explains: fructose-containing sugars cause obesity not by calories but by turning on the fat switch:

“Those of us who are obese eat more because of a faulty ‘switch’ and exercise less because of a low energy state. If you can learn how to control the specific ‘switch’ located in the powerhouse of each of your cells – the mitochondria – you hold the key to fighting obesity.”

The ‘switch’ is triggered by the release of uric acid contained in fructose, which contributes to insulin resistance and obesity. So large portions of food and too little exercise are not solely responsible for weight gain.

We have slandered and libelled the most nutritious macronutrient – fat and we have promoted and praised the least nutritious macronutrient – carbohydrate. We don’t need to look far to understand why. The most nutritious foods on the planet are those provided by nature. The most profitable foods on the planet are those provided by food manufacturers.

As the demonisation of real food has gathered pace, fledgling and long-standing food and drink companies have become multi-billion dollar empires. PepsiCo, the world’s largest convenient food and beverage company, is bigger than 60 per cent of the countries in the world. An immense and profitable industry has grown on the back of the low fat, high carbohydrate advice that we invented. Human beings have become high fat and low health in parallel.

When people talk about ‘the obesogenic environment’, they do so as if this were some inexplicable phenomenon that crept up on the world and made everyone fat. We created this obesogenic environment; it did not happen to us. We told people to avoid real food and to eat processed food. We passed legislation to introduce trans fats and sweeteners into our food chain. We allowed our children to be given toys, cartoon characters and junk food by ‘strangers’.

We have facilitated the comprehensive infiltration of the food and drink industry into our dietary advice – nowhere more so than in the fattest nation on earth, America, where we have gone as far as legislating the relationship, so that only the food industry sponsored American Dietetic Association can advise the unsuspecting public. We put cakes, cola and sweets on government posters, pyramids and plates of role model healthy eating. We welcomed food and drink industry funds turning global sporting events into advertising arenas for their products. We continue to revere sports and pop stars, who are paid millions of dollars to endorse products that they likely don’t consume themselves. We care more about the profitability of Kellogg’s and McDonald’s than we do the health of our citizens.

Had we changed our advice for the wrong reasons and to the wrong advice without consequence, we would have been fortunate. We have not been fortunate. We have paid an enormous price for this change; with a tenfold increase in obesity. Furthermore, more people are continuing to become obese and the obese are continuing to become more obese and we have not yet had the first generation born to our most obese generation. It is not unreasonable to say that on the back of one man’s study, first adopted by one American Governor and then the world, we have an obesity epidemic.

As obesity doubled for UK adults between 1972 and 1982 and then almost doubled again by 1989 and then almost another time by 1999, the urgency and desperation to lose weight was palpable. The advice that people were given was the same as the advice that made them overweight in the first place: eat less fat and more carbohydrate. In other words, eat less real food and eat more processed food.

Eat less/do more became such a common mantra that anyone who didn’t ‘get this’ was declared stupid. What these critics didn’t know is that we had evidence going back to the early 20th Century that eat less/do more did not work – Francis G. Benedict, Human vitality and efficiency under prolonged restricted diet, 1919. The level of failure was later quantified at 98 per cent – by Albert Stunkard and Mavis McLaren-Hume in ‘The results of treatment for obesity’, Archives of Internal Medicine, 1959.

Another irony could be that we ignored the brilliant and unbiased study done by Ancel Keys and favoured instead the one where he set out to prove an already held view. In his The Biology of Human Starvation (1950) Keys did the definitive study to show exactly what happens when we manage to restrict calorie intake and that even this can only be achieved ‘in captivity’, due to the hunger that ensues. We know from this Minnesota experiment that calorie restriction results in a disproportionate reduction in energy expenditure and metabolic activity and that the ‘circular reference’ will defeat the dieter in weeks.

As we tried to fix a crisis, without making the connection that we started it, we compounded the challenge by proceeding on the basis of flawed assumptions, both theoretical and empirical.

The theoretical error we made was to simplify the application of the laws of the universe to the world of dieting. We got the first law wrong and ignored the second law. If we had considered both properly, we would have realised that obesity is not a simplistic outcome of energy in (overweight people eat too much) and energy out (overweight people are too sedentary). We would have realised that energy in can only equal energy out if the body makes no internal adjustment whatsoever. Not only is this biochemically impossible, the internal adjustment made by the body, in response to changes in energy intake and energy requirements, is likely to be far greater than any change in fat reserves that the body will make.

Empirically, we got hold of a calorie formula, we know not from where, which we hold to be true and continually prove to be untrue. One pound does not equal 3,500 calories. We will not lose one pound if we create a deficit of 3,500 calories. The most fundamental tenet of the diet world fails basic scrutiny. Worse, seven public and obesity health authorities  the Department of Health, NHS, British Dietetic Association, Dieticians in Obesity Management, Association for the Study of Obesity, National Obesity Forum and National Institute for Clinical Excellence – all failed to prove their formula and none knew from whence it came.

If we carried on teaching children that London is the capital of America, when we knew this to be wrong, there would be uproar. Yet when the hopes of 1.5 billion overweight people depend upon an equally wrong, but vastly more serious, untruth, we continue to lie.

We know that any answer to the obesity epidemic must explain what has changed since around 1980. The answer, therefore, can not be found in something we have been eating for over one hundred thousand years (real food – especially fat). The answer can not be found in anything we have been eating less of during the past thirty years (real food – especially fat). The answer can be found in anything we have not been eating for over one hundred thousand years (processed food – especially carbohydrate). The answer can be found in anything we have been eating more of during the past thirty years (processed food – especially carbohydrate).

Similarly, the answer can not be found in the other half of the energy in equals energy out oversimplification. Sedentary behaviour did not cause the obesity epidemic. Exercise will not cure it.

When we put the following factors together we can see that carbohydrates are uniquely suited to weight gain and uniquely unsuited to weight loss:

  1. Obesity is not a simplistic imbalance of energy in and energy out but a far more complex matter of how, biochemically, the body can store or utilise fat. Carbohydrate is the unique macronutrient that facilitates fat storage and prevents fat utilisation.
  2. Fat and protein calories have jobs to do within the body – they contribute to the ‘up to’ 85 per cent of energy requirement determined by metabolic rate. On the other hand, carbohydrate doesn’t – it needs to be burned as fuel or it will be stored as fat.
  3. Insulin has been called the fattening hormone for good reason. Carbohydrate calories stimulate the release of insulin whereas fat and protein calories do not.
  4. Fat and protein calories have substantial metabolic advantage over carbohydrate calories. A low carbohydrate diet can thus simulate a low calorie diet, by as much as if a 25 per cent reduction in calorie intake had been made, but without the accompanying desire to eat more and do less.
  5. As far back as 1956, studies have shown low calorie diets to be far less effective than low carbohydrate diets.

The food that we have been advising people to eat more of is the very food that enables fat to be stored and disables fat from being utilised. Carbohydrates, not calories, are the critical determinant of obesity and the epidemic thereof.

At the outset I quoted the brilliant University of Florida study of how much people would rather be something else than obese (Colleen S.W. Rand and Alex M. C. Macgregor, ‘Successful weight loss following obesity surgery and the perceived liability of morbid obesity’, International Journal of Obesity, 1991). The precise numbers were that, rather than be obese, 100 per cent of those researched would rather be deaf, 89 per cent would rather be blind and 91 per cent would rather have a leg amputated. Proposed solutions are that we wire the jaws, or staple the stomachs, of our fellow humans. The suggestion that we might return to eating the way that we did, before we needed to invent such drastic procedures, is instead seen as radical.

Our decision to move away from the diet that we have evolved to eat has led to two thirds of the ‘evolved’ world being overweight and a number wishing that they were literally anything else, rather than obese.

As Barry Grove observed, in a presentation to the Weston Price Foundation inaugural European conference in London in 2010, “Man is the only chronically sick animal on the planet.” That’s because man is the only species clever enough to make his own food and the only one stupid enough to eat it.

How many more obese people do we plan to produce before we stop feeding them man-made food? Will the man-made obese ever forgive us for what we have already done? Will we ever forgive ourselves if we make any more? Is it really so preposterous to suggest that we simply return to eating the real food that our planet provides for us? The real food that we used to eat, before we got so fat we’d rather be blind.

Zoë Harcombe is author of The Obesity Epidemic: What caused it? How can we stop it? published in 2010.

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