The Obesity Code. Jason Fung

Speculating on the cause, many identified the refined carbohydrates of sugar and starches. Sometimes considered the father of the low-carbohydrate diet, Jean Anthelme Brillat-Savarin (1755–1826) wrote the influential textbook The Physiology of Taste in 1825. There he wrote: “The second of the chief causes of obesity is the floury and starchy substances which man makes the prime ingredients of his daily nourishment. As we have said already, all animals that live on farinaceous food grow fat willy-nilly; and man is no exception to the universal law.”⁴

      All foods can be divided into three different macronutrient groups: fat, protein and carbohydrates. The “macro” in “macronutrients” refers to the fact that the bulk of the food we eat is made up of these three groups. Micronutrients, which make up a very small proportion of the food, include vitamins and minerals such as vitamins A, B, C, D, E and K, as well as minerals such as iron and calcium. Starchy foods and sugars are all carbohydrates.

      Several decades later, William Banting (1796–1878), an English undertaker, rediscovered the fattening properties of the refined carbohydrate. In 1863, he published the pamphlet Letter on Corpulence, Addressed to the Public, which is often considered the world’s first diet book. His story is rather unremarkable. He was not an obese child, nor did he have a family history of obesity. In his mid-thirties, however, he started to gain weight. Not much; perhaps a pound or two per year. By age sixty-two, he stood five foot five and weighed 202 pounds (92 kilograms). Perhaps unremarkable by modern standards, he was considered quite portly at the time. Distressed, he sought advice on weight loss from his physicians.

      First, he tried to eat less, but that only left him hungry. Worse, he failed to lose weight. Next, he increased his exercise by rowing along the River Thames, near his home in London. While his physical fitness improved, he developed a “prodigious appetite, which I was compelled to indulge.”⁵ Still, he failed to lose weight.

      Finally, on the advice of his surgeon, Banting tried a new approach. With the idea that sugary and starchy foods were fattening, he strenuously avoided all breads, milk, beer, sweets and potatoes that had previously made up a large portion of his diet. (Today we would call this diet low in refined carbohydrates.) William Banting not only lost the weight and kept it off, but he also felt so well that he was compelled to write his famous pamphlet. Weight gain, he believed, resulted from eating too many “fattening carbohydrates.”

      For most of the next century, diets low in refined carbohydrates were accepted as the standard treatment for obesity. By the 1950s, it was fairly standard advice. If you were to ask your grandparents what caused obesity, they would not talk about calories. Instead, they would tell you to stop eating sugary and starchy foods. Common sense and empiric observation served to confirm the truth. Nutritional “experts” and government opinion were not needed.

      Calorie counting had begun in the early 1900s with the book Eat Your Way to Health, written by Dr. Robert Hugh Rose as a “scientific system of weight control.” That book was followed up in 1918 with the bestseller Diet and Health, with Key to the Calories, written by Dr. Lulu Hunt Peters, an American doctor and newspaper columnist. Herbert Hoover, then the head of the U.S. Food Administration, converted to calorie counting. Dr. Peters advised patients to start with a fast, one to two days abstaining from all foods, and then stick strictly to 1200 calories per day. While the advice to fast was quickly forgotten, modern calorie-counting schedules are not very different.

      By the 1950s, a perceived “great epidemic” of heart disease was becoming an increasing public concern. Seemingly healthy Americans were developing heart attacks with growing regularity. In hindsight, it should have been obvious that there was really no such epidemic.

      The discovery of vaccines and antibiotics, combined with increased public sanitation, had reshaped the medical landscape. Formerly lethal infections, such as pneumonia, tuberculosis and gastrointestinal infections, became curable. Heart disease and cancer now caused a relatively greater percentage of deaths, giving rise to some of the public misperception of an epidemic. (See Figure 1.1.⁶)

      Figure 1.1. Causes of death in the United States 1900 vs. 1960.

      The increase in life expectancy from 1900 to 1950 reinforced the perception of a coronary-disease epidemic. For a white male, the life expectancy in 1900 was fifty years.⁷ By 1950, it had reached sixty-six years, and by 1970, almost sixty-eight years. If people were not dying of tuberculosis, then they would live long enough to develop their heart attack. Currently, the average age at first heart attack is sixty-six years.⁸ The risk of a heart attack in a fifty-year-old man is substantially lower than in a sixty-eight-year-old man. So the natural consequence of a longer life expectancy is an increased rate of coronary disease.

      But all great stories need a villain, and dietary fat was cast into that role. Dietary fat was thought to increase the amount of cholesterol, a fatty substance that is thought to contribute to heart disease, in the blood. Soon, physicians began to advocate lower-fat diets. With great enthusiasm and shaky science, the demonization of dietary fat began in earnest.

      There was a problem, though we didn’t see it at the time. The three macronutrients are fat, protein and carbohydrates: lowering dietary fat meant replacing it with either protein or carbohydrates. Since many high-protein foods like meat and dairy are also high in fat, it is difficult to lower fat in the diet without lowering protein as well.

      So, if one were to restrict dietary fats, then one must increase dietary carbohydrates and vice versa. In the developed world, these carbohydrates all tend to be highly refined.

      Low Fat = High Carbohydrate

      This dilemma created significant cognitive dissonance. Refined carbohydrates could not simultaneously be both good (because they are low in fat) and bad (because they are fattening). The solution adopted by most nutrition experts was to suggest that carbohydrates were no longer fattening. Instead, calories were fattening. Without evidence or historical precedent, it was arbitrarily decided that excess calories caused weight gain, not specific foods. Fat, as the dietary villain, was now deemed fattening—a previously unknown concept. The Calories-In/Calories-Out model began to displace the prevailing “fattening carbohydrates” model.

      But not everybody bought in. One of the most famous dissidents was the prominent British nutritionist John Yudkin (1910–1995). Studying diet and heart disease, he found no relationship between dietary fat and heart disease. He believed that the main culprit of both obesity and heart disease was sugar.^{9, 10} His 1972 book, Pure, White and Deadly: How Sugar Is Killing Us, is eerily prescient (and should certainly win the award for Best Book Title Ever). Scientific debate raged back and forth about whether the culprit was dietary fat or sugar.

       THE DIETARY GUIDELINES

      THE ISSUE WAS finally settled in 1977, not by scientific debate and discovery, but by governmental decree. George McGovern, then chairman of the United States Senate Select Committee on Nutrition and Human Needs, convened a tribunal, and after several days of deliberation, it was decided that henceforth, dietary fat was guilty as charged. Not only was dietary fat guilty of causing heart disease, but it also caused obesity, since fat is calorically dense.

      The resulting declaration became the Dietary Goals for the United States. An entire nation, and soon the entire world, would now follow nutritional advice from a politician. This was a remarkable break from tradition. For the first time, a government institution intruded into the kitchens of America. Mom used to tell us what we should and should not eat. But from now on, Big Brother would be telling us. And he said, “Eat less fat and more carbohydrates.”

      Several specific dietary goals were set forth. These included

      •raise consumption of carbohydrates until they constituted 55 percent to 60 percent of calories, and

      •decrease fat consumption from approximately 40 percent of calories to 30 percent, of which no more than one-third should come

      from saturated fat.

      With