The Obesity Code: Unlocking the Secrets of Weight Loss

In The Obesity Code, Fung argues that a diet low in refined carbohydrates, alongside intermittent fasting, is central to achieving long-term weight loss. As such, Fung is part of a long line of commentators identifying carbohydrates as key contributors to the global obesity epidemic. An early proponent of limiting carbs was the French lawyer and politician Jean Anthelme Brillat-Savarin who posited a connection between carbohydrates and obesity in his 1825 book The Physiology of Taste. A few decades later, a formerly obese English undertaker named William Banting repeated Brillat-Savarin’s ideas in his best-selling pamphlet, Letter on Corpulence, Addressed to the Public (97). It was not until the middle of the 20th century, however, that medical professionals began linking carbohydrates to obesity. In 1953, for example, Dr. Alfred Pennington published an editorial in the New England Journal of Medicine highlighting the role of carbohydrates in weight gain. In 1967, Dr. Irwin Stillman brought the connection between carbohydrates and obesity to popular attention in his book, The Doctor’s Quick Weight Loss Diet, which sold over 2.5 million copies (97). Stillman surmised that a diet high in protein and low in carbohydrates would result in weight loss because dietary protein takes more time and energy to metabolize than carbs. He reportedly lost 50 pounds by drastically reducing his intake of carbohydrates and following a diet comprising up to 90% protein (97).

Robert Atkins is among the best-known figures associated with the low-carb diet. A cardiologist with a practice in New York City, Atkins radically reduced his intake of carbohydrates after failing to lose weight following a conventional low-calorie, low-fat diet (96). His success led him to prescribe the diet to his patients, who also lost weight. In 1972, Atkins published his bestselling book, Dr. Atkins’ Diet Revolution: The High Calorie Way to Stay Thin Forever, which recommended restricting carbs and following a high-protein, high-fat diet. Atkins argues that severely curbing carbs keeps insulin low, reduces hunger, and leads to weight loss. Atkins’s ideas elicited immediate responses from health experts, who were uniformly critical. The American Medical Association’s Council on Foods and Nutrition, for example, issued a blistering attack on Atkins’s book in 1973 while physicians voiced concerns that the diet’s high-fat content would lead to coronary disease. Nevertheless, Dr. Atkins’ Diet Revolution garnered a large following and influenced other authors, such as Rachael and Richard Heller, who published The Carbohydrate Addict’s Diet in 1993, and Dr. Richard Bernstein, who published Dr. Bernstein’s Diabetes Solution in 1997. The low-carb diet reached even greater popularity in 2002 with the publication of Gary Taubes’s “What If It’s All Been a Big Fat Lie,” a the New York Times article arguing that dietary fat is harmless to human health. Dr. David Jenkins’s development of the glycemic index in the 1980s also advised reducing carbohydrates, specifically those that raise blood sugar levels, though his work was largely aimed at academic readers.

The Obesity Code builds on generations of research on low-carb diets. However, Fung refines existing arguments, urging readers to reduce their consumption of all foods that raise insulin levels, including, but not limited to, highly processed carbohydrates. Fung also recommends eating more foods that control insulin spikes, notably, fats, and practicing intermittent fasting to combat insulin resistance. In other words, he identifies high, persistent insulin levels as the primary cause of obesity. Although Fung’s approach to weight loss has become popular in recent years, it is not without detractors. Heidi Silver, for instance, points out that intermittent fasting studies have focused on animal, rather than human, subjects. As Carol Aguirre, observes, moreover, The Obesity Code fails to take individuals’ lifestyles and metabolisms into account, ignoring critical information that might influence weight loss (Healthline).