Dr. Jason Fung, a Toronto-based kidney specialist, challenges conventional weight loss wisdom in his new book The Hunger Code. Fung argues that obesity stems from hormonal imbalances, particularly chronically high insulin levels, rather than simple calorie counting. His approach focuses on how the body processes calories rather than just their quantity.

Fung cites studies like The Women's Health Initiative, where participants reduced calories by 371 daily and increased exercise by 10%, yet saw no weight loss after seven years. He explains that when people simply eat less, their basal metabolic rate decreases, creating a counterproductive cycle. The timing of meals also matters significantly, with late-night eating producing 25% higher insulin levels than morning meals.

Fung recommends eating foods that minimize insulin spikes, such as meat, fish, eggs, vegetables, and healthy fats. He emphasizes meal order, suggesting eating protein and fiber before carbohydrates to reduce insulin response by up to 50%. His approach aims to reset the body's "fat thermostat" by addressing hormonal factors like GLP-1, ghrelin, and leptin that regulate hunger and fat storage. By focusing on hormonal balance rather than calorie restriction, Fung offers a science-based alternative to traditional dieting methods.