In 2009, Professor Robert Lestig, a pediatric endocrinologist at the University of California who specializes in the treatment of childhood obesity, delivered a 90-minute lecture entitled “Sugar, a Painful Reality. The speech pointed out forcefully: sugar is the culprit of the obesity epidemic! Speaking of which, I believe that many girls who have lost weight have a deep understanding of the weight loss when the meal are afraid to eat more than one bowl there! But if you use your brain again, think deeper, you may ask a question: food intake of cholesterol is not the real culprit of those flesh on the belly? If not, why do we have to endure so hard to lose weight, half of the greasy food are afraid to touch it? In fact, the “lipid hypothesis” comes from the famous “Seven Countries Study” done by American physiologist Ancel Keys in 1958. He proposed: meat and dairy products contain a lot of “unhealthy” saturated fat, while vegetable oils and fish, nuts, seeds, etc. belong to the food containing “healthy” fat. The saturated fats that the body gets from foods like red meat, cheese, butter and eggs lead to higher cholesterol levels in the blood, and excess cholesterol is deposited in the coronary arteries. He recruited 12,763 men between the ages of 40 and 59 from seven countries, including the United States, Finland, the Netherlands, Italy, Yugoslavia, Greece and Japan. After the men enrolled in the program, Case examined their diets and heart health after five and 10 years, respectively. From this, he concluded that there was a correlation between saturated fat in food and increased chances of rising blood lipids and heart disease and stroke. The lipid hypothesis was born. But the results of this experiment were not rigorous. Although Keith proved that the occurrence of heart disease was associated with the intake of saturated fat, he did not rule out the possibility that other factors contributed to heart disease. A few years later, the lead Italian researcher involved in the seven-country study, D’Alessandro Menotti (Alessandro Menotti), reviewed the data and found that it was not saturated fat but sugar that was most closely associated with heart disease mortality. The most famous skeptic of the “lipid hypothesis” was John Yudkin, the chief nutritionist in England at the time. When Yudkin looked at the data on heart disease, he was surprised to find that the odds of heart disease correlated with the consumption of sugars rather than fats. He then conducted a series of animal and human experiments in his laboratory. The results of the experiments, like those of others, showed that sugar is converted to fat in the liver before it enters the bloodstream. He also pointed out that humans have been carnivores for a long evolutionary time, and that it was only with the advent of large-scale agriculture about 10,000 years ago that carbohydrates became a major part of the human diet. Sugar, as a simple carbohydrate with fiber and other nutrients removed, has only been in the Western diet for 300 years; from an evolutionary perspective, 300 years is like one second of human history, as if it were the first time humans consumed the stuff. A comparison shows that saturated fats are closely related to human evolution and are present in large amounts in breast milk. Our mothers’ milk is filled with large amounts of saturated fat. In Yudkin’s view, our health problems are more likely to be caused by new foods that have recently emerged, and should not be blamed on staple foods that have been consumed since prehistory. So when one senator asked Yudkin if it was true that a high-fat diet did not cause coronary heart disease, Yudkin’s answer was that a diet low in sugar and high in fat was a better way to lose weight than a low-fat diet.