Copyright © 2009
by Daniel Matthew Korn

All Rights Reserved

As we have seen, weight gain is closely connected with poor health. By various measures, human health both improved and declined beginning in the twentieth century. We are experiencing lower rates of infectious disease along with higher rates of chronic disease. It is usually assumed that this is because modern medicine has improved at the same time the modern diet has worsened. However, there is an alternative theory to account for these changes. Advocates of a return to the hunter-gatherer diet believe that high rates of infectious disease prior to the twentieth century masked the effects of obesity and chronic disease which resulted from the shift away from the hunter-gatherer diet.

Without the transition to agriculture, large cities could not have existed in the ancient world. Physically inactive adult subjects in a test of the hunter-gatherer diet were offered up to 11 pounds of food a day, an amount most could not eat.¹ The equivalent number of calories from wheat would weigh over 80% less, under two pounds, and would be even less bulky. In order for cities to appear, the surrounding farmland had to be able to supply them with food. Because shipping was so expensive, grains provided the majority of the calories eaten by those dwelling in large cities until the twentieth century.

The fossil record shows that humans became slightly shorter and experienced more dental cavities after the transition from hunting and gathering to farming. Fossils give only incomplete information about rates of diseases like cancer, heart disease, and obesity, which do not necessarily leave marks on skeletons. However, the remaining tribes of hunters and gatherers around the world are essentially free of the diseases which have become common in the modern world. This has led some to claim that we are experiencing higher rates of chronic disease because the combination of a grain-based diet and advances in medicine and sanitation enable longer life. According to this theory, the people who are experiencing poor health as they age are those who would have died prematurely in earlier times. Supposedly, human health declined due to the adoption of the agrarian diet, but the full extent of the deterioration was masked by high death rates from infectious and parasitic diseases.

While humans started eating grains around twelve thousand years ago, humans and their ancestors ate a grain-free diet for many millions of years before the cultivation of grains was initiated. On a real hunter-gatherer diet, all meats must come from grass-fed animals, free range poultry, or wild fish. Consumption of conventionally raised meats is not permitted. It has been argued that this is the diet our bodies have evolved to eat, and all grain consumption is inherently bad. However, it has also been argued that this diet is very rich in fruits and vegetables, foods that have a very low caloric density. This observation forms the basis of another theory of weight gain.

We have already seen that increased consumption of fruits and vegetables reduces hunger and leads to weight loss, yet the vitamins and minerals in which fruits and vegetables are rich do not seem to cause this effect when they are given as supplements. Our records indicate we are not getting fewer calories from fruits and vegetables than was the case a century ago, but we may be eating fewer bulky vegetables. Perhaps much of our vegetable consumption today is calorically dense, such as potatoes, and we are eating fewer high volume leafy green vegetables. After all, people experience massive weight loss after surgery to make their stomach smaller. All this surgery does is give the body the perception that the stomach is full, and this is what happens when high volume foods such as fruits and vegetables are consumed. This would explain not only why we did not become overweight on the hunter-gatherer diet, but why we are only becoming overweight now.

If either the agrarian theory or the food volume theory is correct, eating the way our hunter-gather ancestors did should cause weight loss and better health. This diet is sometimes referred to as the Paleolithic diet or the Caveman diet. One experiment performed at a zoo in the United Kingdom attempted to test its effectiveness. Overweight volunteers for this experiment spent close to two weeks living in tents in an animal enclosure. They were allowed to eat and drink foods that were available to hunter-gatherers, including water, broccoli, carrots, radishes, tomatoes, strawberries, apricots, bananas, mangoes, melons, figs, honey, and nuts, in amounts that most could not finish. For part of the experiment, they were also given limited portions of wild salmon, which is high in anti-inflammatory omega-3 fats. The results of this experiment stunned even the organizers. In the short period of the study, the average participant lost about nine pounds. In addition to the weight loss, after the effects of caffeine withdrawal passed the participants experienced elevated mood and increased energy levels.²

As we have seen previously, other experiments have demonstrated that high fruit and vegetable consumption cause decreased hunger and increased weight loss. Most of these experiments do not have subjects get the vast majority of their calories from fruits and vegetables. It is interesting to note that similar experiments have had similar results. Dr. Joel Fuhrman, a family physician who specializes in nutrition, is the author of Eat to Live. In his book, Dr. Fuhrman advocates a diet in which over half of the calories come from raw vegetables, and most of the rest come from fruits and legumes. He notes that in the first two weeks of this diet, it is not uncommon for his patients to lose a pound a day, an amount that later slows.³ These short-term results are similar to the results seen in the U.K. study, and Dr. Fuhrman documents cases and studies of obese people who have achieved a healthy weight and maintained it for years by eating a diet based on fruits, vegetables, and legumes.

The agrarian diet, which involves growing crops rather than scavenging and hunting, began to appear around twelve thousand years ago. There were some rare examples of obesity among the rich in the early agrarian period. However, alcohol first began to appear around the time when the agrarian diet was developed.⁴ Alcohol is a toxin that can deplete the body of nutrients, cause inflammation, and lead to obesity and many other chronic diseases. We lack the data to know with certainty how many cases of obesity occurred twelve thousand years ago, or if the people who were killed by infectious disease would have become chronically ill if they had lived long enough.

There are, however, several problems with the idea that the agrarian diet is responsible for modern obesity. As we have seen, Japan has the longest life expectancy of any major modern country. One of the reasons for this is undoubtedly its very low obesity rate, which was about 3% in 2005. Another reason is its very low rate of chronic disease, which is likely related to its low rate of obesity. In Japan, the people who are overweight are likely to be those who have adopted foods from the Western diet, and these are the same people who are more likely to suffer from chronic diseases. If it were not possible to live a long life and be healthy on the agrarian diet, we would expect the people who are living the longest and are the healthiest in the world to have consumed a diet low in grains, but they have not. Between 1961 and 2002, between a quarter and slightly less than half of the calories in the Japanese diet came from rice, primarily white rice.⁵ This is not the only diet containing grain which results in low body weight.

Despite the fact that there have long been studies showing a strong inverse correlation between consumption of whole grains and obesity, controlled experiments have only recently begun to be performed. One experiment put two groups of obese people on a restricted calorie diet and encouraged the consumption of fruits, vegetables, and lean meats. The first group ate refined grains, and the second ate whole grains. At the end of the experiment, both groups had lost weight, but the whole grain group had lost significantly more abdominal fat. Interestingly, the whole grain group had a 38% decrease in levels of C-reactive protein, a marker for inflammation, while levels in the refined grain group were unchanged. Many chronic diseases are caused by inflammation, which leaves us with a problem. The Japanese eat huge amounts of inflammatory refined grains; close to half of their calories came from rice in the 1960s.⁶ The rural Thai in the 1950s study stayed lean while eating about 80% of their calories as white rice. The Bangladeshi people have stayed lean while eating over 70% of their calories as white rice.

As in Japan, in China weight gain is associated with consumption of the Western diet, including in the province of Guangdong. This province is the home of Cantonese style cooking, one of eight schools of Chinese cooking. Americans are familiar with this type of cooking, as it is similar to the food most commonly served in Chinese restaurants in the U.S. Everything we think we know about refined grains tells us that the Cantonese should gain weight and experience chronic disease, yet they do not. They gain weight when they adopt the Western diet—a diet we associate with refined sugars, inflammatory fats, refined grains, processed foods, and low consumption of fruits and vegetables. These are all factors that have been associated with weight gain in experiments, but we have a problem.

Authentic Cantonese food, like American style Cantonese food, contains white rice, meats from grain-fed animals, refined sugars, and refined oils. A low percentage of its calories come from fruits and vegetables. Livestock have been fed at least partially on rice in the Far East for hundreds of years. Cantonese pigs are fed “anything available,” in a manner similar to the way many cattle are raised on American farms.⁷ Everything we think we know about weight gain says that this diet should produce obesity, yet the traditional Cantonese diet did not cause obesity in China through the twentieth century. Obesity has occurred in significant numbers in recent years, but it has been among people who have started eating Western style food.⁸ Currently accepted diet theories cannot explain this, so it appears we are still missing something very important in our quest to understand the causes of weight gain in the modern diet.⁹

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