LOW FAT. Low carb. Vegan. Atkins. Paleo. South Beach. Zone. As television shows, magazine covers, podcasts, and books release an endless flood of diet advice, the average person finds it difficult at best to know how to find a sustainable method of weight loss. The latest scientific debate in the world of nutrition is no less heated: are all calories created equal?
David Ludwig, professor of pediatrics at Harvard Medical School and of nutrition at the School of Public Health, who specializes in endocrinology and obesity, rejects the popular belief that overeating causes weight gain. Instead, he asserts, the process of getting fatter causes people to overeat. Even though many biological factors—genetics, levels of physical activity, sleep, and stress—affect the storage of calories in fat cells, he points out that only one has a dominant role: the hormone insulin. “We know that excess insulin treatment for diabetes causes weight gain, and insulin deficiency causes weight loss,” he says. “And of everything we eat, highly refined and rapidly digestible carbohydrates produce the most insulin.”