In this series, we will look at the basics of metabolism and discuss the very well-known science around obesity. Many of the diseases that bedevil humanity flow from obesity, including cancer and Type 2 diabetes, and so understanding metabolism and the causes of obesity is ground zero in the fight for a long life and good health.

In September of 1955, the most important heart attack in the world occurred. President Dwight Eisenhower, the hero General from World War 2, had a heart attack which was not fatal, but was significant enough for his doctors to begin a course of treatment which included revising his diet. Eisenhower was not overweight, had quit smoking years earlier, and exercised regularly. He also did not have elevated cholesterol levels but unfortunately, he had a heart attack just when the American medical establishment was putting in to practice a theory that had been building towards orthodoxy over the decades.

Heart disease, it had been decided, was the result of eating dietary fat, otherwise known as animal fat. Animal fat in meat, in eggs, in cheese, and in many other foods, including the lard used in baked goods, was declared the cause of heart disease because it raised the level of cholesterol in circulation. To combat the possibility of another heart attack, Eisenhower was put on a diet with limited animal fat and plenty of ‘healthy’ food like Melba toast. He did not lose weight as predicted, which was frustrating to him. In the diaries left by his doctors, they reported that Eisenhower dieted as was recommended, and cut out nearly all animal fat, including all butter. He was, they said, very cranky from hunger after he stopped eating breakfast and then lunch.

Eisenhower’s experience with a low-fat diet, however, did not stop the low-fat train from leaving the heart attack station. Under the direction of an influential food scientist named Ancel Keys, the fat-cholesterol hypothesis gained traction and any lack of evidence regarding its veracity was ignored or explained away.

Dissenting voices were fought and careers were ruined in order to keep the science around the connection between fat and heart attacks in place. According to Gary Taubes in Good Calories, Bad Calories, “…those who argued that dietary fat caused heart disease accumulated the evidential equivalent of a mythology to support their belief. These myths are still passed on faithfully to this day.

The story of how the fat-cholesterol-heart attack hypothesis gained such traction is a tale for the ages of flawed science and career scientists building up personal capital in a theory. It isn’t true and Taubes, as well as many other science writers, have taken Keys to task for suppressing any evidence that his theory did not hold up to intense scrutiny.

For decades, low-fat food was sold using cheap ingredients that made food manufactures rich. When the counter-culture notions of peace and kindness came in to vogue in the sixties, the whole idea of meat eating came to be thought of as a perfect metaphor for ugly American excess. Dietary fat, including all pork, steak, bacon, butter, were products of the cowboy-oriented livestock industry and eating them was suddenly considered a moral as well as scientific mistake. Culture took over from science and fat was discouraged and discredited as a primary food ingredient.

The epidemic of obesity began right about the time that fat eating fell out of favor. The reason is as logical as it is obvious. There are only three food macros; fat, protein, and carbohydrates. Fat is often paired with protein in foods like meat, and so if one is instructed to eat less fat, the only alternative is carbohydrates. Carbohydrates with no fat in them don’t taste good and so to replace the palatability of fat, sugar was suddenly put in EVERYTHING from bread to peanut butter. It was in this period that the ‘hyper-palatable’ food items came to be, such as breakfast cereal, donuts, potato and corn chips, and hundreds of other items that were low in fat, but otherwise highly palatable. This made the insulin train leave the station. From a business standpoint, these foods had another virtue; they did not produce a feeling of satiety, which was promoted as a benefit: “No one can eat just one!” was the widely promoted marketing slogan of Lays potato chips. If the goal is to sell more, then not filling someone up so they’ll eat more is awesome!

And so, here we are, with more heart disease, but we also have obesity and Type 2 diabetes to go along with it. All of this is the bitter fruit of the fat-cholesterol theory that made fat the enemy and moved carbohydrates in to the preferred position in the American diet.

Lays potato chip ad from the 1960s