[Book Review] There Is a Reason Diets Fail... The Problem Lies in the "Weight Set Point"

Jenkinson "How Food Shapes Our Bodies"
"Obesity is a disease, not solved by willpower"
Resetting the "weight set point" is key
Exercise and diet alone are not enough
Sugar, fructose, and vegetable oils must be eliminated

In the past, depression was often viewed simply as a lack of willpower. Advice such as "just toughen up and your feelings of sadness will easily go away" caused significant pain to those suffering from what is sometimes called a cold of the mind. This perspective is similarly applied to obesity. Contrary to the simplistic prescription of "just eat less and move more with strong determination," the reality is far more complicated, leaving many people discouraged.

However, Andrew Jenkinson, who has dedicated 20 years to obesity research at University College Hospital London, states that "weight control is not a matter of willpower, but rather an issue of how we perceive and understand food."

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In 2023, Mr. Johnson, who weighed 120kg, underwent a sleeve gastrectomy, removing two-thirds of his stomach. This surgery physically reduced the amount of food he could consume. Medical students observing the procedure at the time questioned, "If someone can exercise willpower and restrain themselves, is surgery really necessary?" In response, the author asserted that when the hormones leptin and insulin are not properly regulated, no amount of determination can make willpower effective.

Leptin is a hormone secreted by fat cells that influences appetite. It notifies the brain of the body's fat stores and adjusts energy expenditure accordingly. When leptin levels rise, the hypothalamus detects this, increasing the feeling of fullness and reducing appetite. However, Jenkinson explains that when people consume foods high in sugar and refined carbohydrates, insulin produced by the pancreas interferes with leptin signaling, causing the brain to misinterpret the body's state. As a result, appetite actually increases and energy expenditure decreases.

At this point, the stomach secretes a powerful appetite hormone called ghrelin. This hormone perceives weight loss as a crisis, stimulating the hypothalamus and triggering intense hunger. Although reducing food intake may lead to some weight loss, the resulting fatigue and weakness persist, eventually driving people back to food and causing diets to fail, the author emphasizes. Sleeve gastrectomy blocks the production of the ghrelin hormone at its source, and the author views this as a form of disease treatment. "People often attribute obesity to greed and laziness, but in reality, these behaviors are symptoms of an illness."

So, is it impossible to lose weight through exercise alone? The author says yes. The body's basal metabolic rate is highly adaptive, so when food intake decreases, energy expenditure also drops to maintain existing body weight. In fact, according to research by American anthropologist Herman Pontzer, the daily energy expenditure of African hunter-gatherers who walk 19,000 steps a day was similar to that of office workers in major U.S. cities. The author analyzes that this is because hunter-gatherers move much less and sleep more deeply during periods of rest.

This is where the concept of "weight set point" becomes important. The author explains that the weight set point is determined by a combination of genetics and environment, and varies from person to person depending on factors such as food types, stress, and sleep patterns. While it can make weight loss difficult, it also prevents excessive weight gain. This explains why some people do not gain weight no matter how much they eat.

Ultimately, the core of this book lies in how to adjust the weight set point. Based on the fact that the number of obese people has surged in the 1,500 years since the introduction of sugar, the author emphasizes that it is possible to alter the weight set point by controlling the intake of sugar, fructose, and vegetable oils. Vegetable oils, often thought to be healthy, include sunflower oil and canola oil, but the author identifies them as risk factors for heart disease. In fact, a 2016 study by the U.S. National Institutes of Health found that, when comparing two groups from 1968 to 1973?one consuming a diet high in saturated fat and the other consuming a diet high in vegetable oils?the latter group had lower cholesterol levels but a higher rate of early mortality.

The author recommends an effective weight loss method that involves avoiding foods containing sugar, fructose, and vegetable oils, combined with exercise. The suggested exercise is high-intensity interval training, which involves repeating 30 to 45 seconds of intense activity followed by 90 seconds of rest, using muscles vigorously. This lowers the weight set point and promotes fat burning. Interestingly, the author adds that fat is not excreted through the digestive system, but rather is reduced through breathing.

The book also impressively covers how to form habits through 66 days of repetition, the claim that salt or calorie content in food does not significantly affect obesity, and the proper use of diet drugs such as Wegovy.

For those who have failed at dieting by relying solely on willpower, this book provides a solid, knowledge-based sense of satisfaction. However, the somewhat tentative expressions such as "it is said that..." detract slightly from the credibility of the content.

How Food Shapes Our Bodies | Written by Andrew Jenkinson | Translated by Pyo Miyeong | Hyunamsa | 308 pages | 22,000 KRW