Copyright © 2009
by Daniel Matthew Korn

All Rights Reserved

There are probably few things as likely to confuse a potential dieter as fat. While almost everyone agrees that highly refined vegetable oils and trans fats are unhealthful, the merits of other types of fat are subject to debate. A very vocal group of people believes that the best diet is high in protein and fat, while another group claims fat should be avoided to lose weight, and a third group insists we avoid “bad” fats and eat “good” fats. According to these commonly expressed theories, fat either causes, reverses, or may cause weight gain in certain cases. These are, of course, mutually exclusive ideas. At most, one of them can be correct. While we cannot easily perform an experiment ourselves to test which is correct, we can look at real world data and other people’s experiments. Even someone who does not have scientific knowledge or medical education can learn a lot just by looking at real world data.

The idea that fat causes heart disease and weight gain is a relatively old one. That it was commonly believed is evidenced by the surprise the Irish physician Samuel Black expressed in 1819 on discovering the low rate of heart disease the French experience, despite diets high in saturated fats. This contradiction between the expected and actual results of the French diet on the citizenry of France became known as the “French Paradox.”

Today the French still eat a diet high in all fats, including saturated fat. They are high consumers of red meat, cheese, butter, and cream, and they drink an average of 11.4 liters of alcohol per year, compared to 8.6 liters per year for Americans. Despite its high fat diet and high rate of alcohol consumption, France still has a relatively low rate of heart disease.¹

Some scientists have questioned that a paradox really exists, arguing that heart disease rates in France are high, but they are not being properly counted or reported. What is not in dispute is that, despite eating significantly more fat than Americans, the percentage of people who are obese (BMI ≥ 30) in France is less than a third of the percentage in the U.S.² Higher fat consumption is not keeping the French from being thinner than Americans, even while they exercise less and drink more alcohol. This is fairly strong evidence that eating fat does not necessarily make people fat. Of course, there is always the possibility that the French are thin because they have a gene that protects them from gaining weight. So let us look at a people who have stayed thin while eating a very high fat diet but who have gained weight upon adopting a lower fat diet.

We can see echoes of Dr. Black’s surprise in 1819 in the October 2004 issue of Discover Magazine. Perhaps invoking the French Paradox, the article about the Inuit asks, “How can people who gorge on fat and rarely see a vegetable be healthier than we are?”³ In almost two hundred years, the common assumption that fat causes obesity has not changed.

The Inuit, often called Eskimos in the United States, traditionally ate a diet that included walrus, ringed seal, bearded seal, beluga whale, polar bear, berries, and fireweed. The Inuit believed their diet kept them warm and strong. However, the main reason they consumed this diet was due to the fact that they had little choice. It is very difficult to grow food in the Arctic, although the Inuit do gather plants that are naturally available. Very few calories in the Inuit diet come from these plants. Overall, 75% of the diet’s calories are from fat.

If a high fat diet caused obesity, we would assume that Inuit who gave up their traditional diet and shifted towards a comparatively lower fat Western diet would be thinner and healthier. However, exactly the opposite has been occurring. Those Inuit who have given up their traditional diet in favor of the Western diet have experienced obesity, diabetes, high blood pressure, and cardiovascular disease.⁴

This is even more convincing evidence that fat and meat consumption does not cause obesity. With the French, the argument can be made that there is a genetic cause for the low rate of obesity. Our genes certainly do not make us fat, but they do allow us to become fat. One could argue that the French have a high prevalence of a gene that keeps them from putting on weight, but we know that this is not the case with the Inuit. The Inuit who maintain their traditional high fat diet remain lean. The Inuit who are gaining weight do so as their consumption of fat and meat decreases. Fat and meat cannot be the cause of their weight gain. Since both groups are living in the same area, environmental factors can be ruled out as well.

In 1972, Dr. Robert Atkins, an American internist and cardiologist, released a book titled Dr. Atkins’ Diet Revolution. Over the next 30 years, he wrote 14 more books, in which he claimed that it was not fat that was responsible for unhealthy weight gain, but refined carbohydrates. Atkins believed that sugar, flour, and high-fructose corn syrup were responsible for the rise of metabolic disorders of the 20^th century. He also felt that wrongly focusing on fat as the cause of weight gain had made the problem much worse.⁵ His ideas were very controversial, but they were convincing to many people. At the height of his diet’s popularity in 2004, almost 10% of American adults were on a low carbohydrate diet.⁶

While conventional science was originally dismissive of Atkins, by attracting so many adherents he made the diet so mainstream that science could not ignore him. Several experimental studies were performed comparing his diet to more traditional diet programs. The results were mixed. One study concluded that there was an advantage in weight loss, but it was due to a loss in water weight.⁷ Another found no major benefit compared to traditional diets, with some harmful side effects.⁸ However, what is most interesting is what was not reported as a result in the studies. People who were put on a very high fat diet did not gain weight. Many of them lost weight. Notably, these were people who were already overweight, which means they could not have been genetically prone to thinness.

These short-term studies show that dietary fat content, at least by itself, is not what is responsible for weight gain. This is a remarkable conclusion. However, the Atkins diet does not appear to hold the secret to weight loss. Between 2004 and 2005, the popularity of low carbohydrate diets fell from about 10% of American adults participating to closer to 2% because, despite achieving some results, most dieters did not reach their ideal weight.⁹

In the 1950s, people living in Europe, especially in Crete, had almost no obesity. This was despite the fact that over 40% of their caloric intake was from fats. The main fat of the diet in Crete was olive oil.¹⁰ This gave rise to another popular diet, the Mediterranean diet, which has been less controversial than the Atkins diet.

Olive oil is promoted as a “good” fat, while saturated fats from animals are “bad” fats. Although this has been uncontroversial, it has unfortunately not been a complete theory of weight control. Today the people of Crete eat amounts of olive oil comparable to levels of consumption in the 1950s, but now over half of them are overweight. This is despite the fact that there has been no change in olive oil consumption.

When we put all of these examples together, they suggest that the overall level of fat consumption cannot explain the modern increase in the prevalence of obesity. The French are eating high levels of fat but remaining relatively thin. The traditional Inuit diet was 75% fat, but the Inuit remained thin, developing high rates of heart disease, obesity, and diabetes only when they adopted the relatively lower fat Western diet. Overweight followers of the Atkins diet restricted themselves to an almost purely protein and fat diet and were even shown to lose some weight. A diet rich in olive oil has not prevented the people of Crete from becoming overweight.

Despite their inability to explain the increasing prevalence of obesity, these examples do not rule out the idea that some fats are helpful and some are harmful. Yet, from the Irish physician Samuel Black expressing surprise at the low level of heart disease in the French, to the modern medical establishment’s horror over the Atkins diet, to the surprise expressed in Discover Magazine at the low levels of cardiovascular disease, diabetes, and obesity observed in the Inuit on their high fat diet, the belief that all fat consumption leads to weight gain is still accepted unconditionally by many. If this is really not the case, how is it possible that we could be so wrong for so long? Doesn’t there have to be something to explain away these paradoxes?

What has really happened here is that we have fallen into a common error in understanding statistical data. We have wrongly assumed that, when two things are associated, one causes the other. If we look at the fat consumption of most countries and the rate of people who are overweight in those countries, as fat consumption goes up, people tend to be more overweight. It has seemed obvious to most people who have observed this correlation that fat consumption was what was causing people to be overweight.

However, the vast majority of fat consumption comes from meat and dairy products. In comparing the amount of fat in the diets of different countries, the correlation between animal product consumption and fat consumption is over 90%.¹¹ As countries become richer, on average their people consume more meat and dairy products, most of which are derived from modern farming techniques. The type of fat contained in most of today’s meat and dairy products is very different from what it was traditionally. Thus, it is not just that as populations of different countries eat more fat their populations become fatter. As countries become richer, many of their people eat more meat and dairy products that are more available, as well as different in fat content, because of modern farming techniques. We have been confusing the effects of high fat consumption with the effects of increased wealth and the changes in agricultural techniques that have helped to make high fat consumption possible. This is why animal fat consumption in the United States appears to harm health, but in France it does not. The type of fat and the nutrient content of the fat are different in the two countries.

In the nineteenth century, meat consumption was very low compared to today. Meat was considered a prestige food in Europe, Asia, and Latin America, with the rich eating much more meat than the poor.¹² In twenty-first century America and Europe, most of us are rich by comparison, despite current economic woes. Increased wealth has gone hand in hand with weight gain in some countries, including the United States, the United Kingdom, Mexico, and Greece.

People in other countries, such as France, Norway, Japan, and South Korea have stayed quite thin. The rate of severely overweight people in Japan and Korea is over 90% less than in the United States. In France, it is over 70% less than in the United States.¹³ The people in these countries have maintained leaner bodies despite living in developed, urban and highly technologically advanced societies.

A large amount of weight loss research has been based on examining the differences between countries in the quantity of fat consumed. However, the idea that even certain types of fat are responsible for weight gain does not explain the rising prevalence of obesity. If the amount or type of fat consumed were the sole cause of weight gain, all of the low fat diets of the twentieth century would be effective, and people on the Atkins diet would all have gained weight.

  Last Chapter       Next Chapter 

Citations:

¹ Core Health Indicators." World Health Organization Statistical Information System. 3/31/2009 http://www.who.int/whosis/.

² Spencer, Mimi. "Let them eat cake." Observer. 4/04/2009 http://www.guardian.co.uk/lifeandstyle/2004/nov/07/foodanddrink.features11.

³ Gadsby, Patricia. "The Inuit Paradox." Discover Magazine. 4/04/2009 http://discovermagazine.com/2004/oct/inuit-paradox.

⁴ Dewailly, Eric. "n-3 Fatty acids and cardiovascular disease risk factors among the Inuit of Nunavik." American Journal of Clinical Nutrition. 4/04/2009 http://www.ajcn.org/cgi/content/abstract/74/4/464.

⁵ Atkins, Robert C. Dr. Atkins' Diet Revolution Bantam, 1972

⁶ Kaufman, Wendy. "Atkins Bankruptcy a Boon for Pasta Makers." National Public Radio. 4/04/2009 http://www.npr.org/templates/story/story.php?storyId=4783324.

⁷ "Carbs may be worse for heart than fatty foods." MSNBC. 4/04/2009 http://www.msnbc.msn.com/id/15625548/.

⁸ Johnston, Carol S. "Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets." The American Journal of Clinical Nutrition. 4/04/2009 http://www.ajcn.org/cgi/content/abstract/83/5/1055.

⁹ "Atkins diet." Wikipedia. 4/04/2009 http://en.wikipedia.org/wiki/Atkins_diet.

¹⁰ Kafatos, A., A. Diacatou, G. Voukiklaris, et al. 1997. "Heart disease risk-factor status and dietary changes in the Cretan population over the past 30 years: the Seven Countries Study." American Journal of Clinical Nutrition 65 (6):1882-86.

¹¹ Campbell, T. Colin. The China Study. BenBella Books, Inc., 2005. p. 83.

¹² Friedman, Jonathan. Consumption and Identity: Workshop on commodities and cultural strategies. Taylor & Francis, 1994. p. 119.

¹³ Gaetan Lafortune and David Morgan. Health at a Glance: OECD Indicators 2005. London: OECD Publishing, 2005, p. 87.