A new theory is challenging the long-established energy balance model, which suggests that weight gain is caused by an imbalance between energy intake and energy expenditure. According to researchers at Harvard Medical School, the alternative carbohydrate-insulin model provides a better explanation for the rise in obesity. The energy balance model has been the basis for dietary guidelines for over a century, recommending that people reduce their calorie intake and increase physical activity to combat obesity. However, the carbohydrate-insulin model suggests that it is not excessive calorie intake, but rather modern, highly processed foods with a high glycemic load that are the main cause of obesity.
According to the Centers for Disease Control and Prevention, over 40% of adults in the US are already obese, and the World Health Organization reports that obesity and overweight have reached epidemic proportions in Europe. The energy balance model suggests that weight gain occurs when energy intake exceeds energy expenditure, which is exacerbated by low physical activity levels. However, the carbohydrate-insulin model suggests that hormonal responses to highly processed carbohydrates fundamentally alter metabolic functions, leading to fat storage and weight gain. These foods trigger a strong insulin response in the body, which suppresses the release of glucagon and leads to more calories being stored in fat cells, leaving fewer calories for muscles and other metabolically active tissues.
The Harvard researchers argue that people should be encouraged to eat the right foods, rather than simply reducing their calorie intake. By reducing the consumption of highly processed carbohydrates, which were introduced during the era of low-fat diets, the underlying drive to store fat can be reduced, resulting in less hunger and effort required to lose weight. While the energy balance model has been the basis for dietary guidelines for over a century, the carbohydrate-insulin model provides a compelling alternative explanation for the rise in obesity.
