Scientists say overeating is not the main cause of obesity – point to more effective weight loss strategies

The perspective published in The American Journal of Clinical Nutrition argues that the root causes of the obesity epidemic are more about what we eat than how much we eat.

Statistics from the Centers for Disease Control and Prevention (CDC) show obesity affects more than 40% of American adults, putting them at higher risk for heart disease, stroke, type 2 diabetes and some types of cancer. The USDA Dietary Guidelines for Americans 2020-2025 further tells us that weight loss “requires adults to reduce the number of calories they get from food and drink and increase the amount expended by activity. physical”.

This approach to weight management is based on the century-old energy balance model which states that weight gain is caused by consuming more energy than we spend. In today’s world, surrounded by highly appetizing, heavily marketed and cheap processed foods, it’s easy for people to eat more calories than they need, an imbalance that is further exacerbated by today’s sedentary lifestyles. By this thought, overeating, coupled with insufficient physical activity, is driving the obesity epidemic. On the flip side, despite decades of public health messages urging people to eat less and exercise more, rates of obesity and obesity-related illnesses have steadily increased.

The authors of “The Carbohydrate-Insulin Model: A Physiological Perspective on the Obesity Pandemic”, a perspective published in The American Journal of Clinical Nutrition, point out the fundamental flaws of the energy balance model, claiming that another model, the carbohydrate-insulin model, better explains obesity and weight gain. In addition, the carbohydrate-insulin model paves the way for more effective and sustainable weight management strategies.

According to lead author Dr. David Ludwig, an endocrinologist at Boston Children’s Hospital and professor at Harvard Medical School, the energy balance model does not help us understand the biological Causes of Weight Gain: “During a growth spurt, for example, teens can increase their food intake by 1,000 calories per day. But does their overeating cause the growth spurt or does the growth spurt cause the teen to be hungry and overeat? “

Unlike the energy balance model, the carbohydrate-insulin model makes a bold statement: Overeating is not the main cause of obesity. Instead, the carbohydrate-insulin model attributes much of the blame for the current obesity epidemic to modern eating habits characterized by excessive consumption of foods with high glycemic load: in particular, processed and rapidly processed carbohydrates. digestible. These foods trigger hormonal responses that fundamentally alter our metabolism, leading to fat storage, weight gain, and obesity.

When we eat highly processed carbohydrates, the body increases the secretion of insulin and suppresses the secretion of glucagon. This, in turn, signals fat cells to store more calories, leaving fewer calories available to fuel muscle and other metabolically active tissue. The brain perceives that the body is not receiving enough energy, which in turn leads to a feeling of hunger. Additionally, the metabolism can slow down in the body’s attempt to conserve fuel. So, we tend to stay hungry even though we keep on gaining excess fat.

To understand the obesity epidemic, we need to consider not only how much we eat, but also how the foods we eat affect our hormones and metabolism. With its claim that all calories are the same for the body, the energy balance model misses this critical piece of the puzzle.

Although the carbohydrate-insulin model is not new – its origins date back to the early 1900s –The American Journal of Clinical Nutrition perspective is the most comprehensive formulation of this model to date, written by a team of 17 internationally renowned scientists, clinical researchers and public health experts. Collectively, they have summarized the growing body of evidence supporting the carbohydrate-insulin model. In addition, the authors identified a series of testable hypotheses that distinguish the two models to guide future research.

The adoption of the carbohydrate-insulin model over the energy balance model has radical implications for weight management and the treatment of obesity. Rather than getting people to eat less, a strategy that usually doesn’t work in the long run, the carbohydrate-insulin model suggests another path that focuses more on what we eat. According to Dr. Ludwig, “The reduction in the intake of rapidly digestible carbohydrates that flooded the food supply during the low-fat diet era decreases the underlying drive to store body fat. As a result, people can lose weight with less hunger and struggle. “

The authors recognize that more research is needed to conclusively test both models and, perhaps, to generate new models that better match the evidence. To this end, they call for constructive discourse and “collaborations between scientists with diverse viewpoints to test predictions through rigorous and impartial research.”

Reference: “The carbohydrate-insulin model: a physiological perspective on the obesity pandemic” by David S Ludwig, Louis J Aronne, Arne Astrup, Rafael de Cabo, Lewis C Cantley, Mark I Friedman, Steven B Heymsfield, James D Johnson , Janet C King, Ronald M Krauss, Daniel E Lieberman, Gary Taubes, Jeff S Volek, Eric C Westman, Walter C Willett, William S Yancy, Jr and Cara B Ebbeling, September 13, 2021, The American Journal of Clinical Nutrition.
DOI: 10.1093 / ajcn / nqab270