Eat That Extra Slice Of Pizza – Overeating May Not Be The Cause Of Obesity. According to the Centers for Disease Control and Prevention (CDC), more than 40% of American adults are obese, putting them at an increased risk of heart disease, stroke, type 2 diabetes, and some types of cancer. Additionally, the USDA’s Dietary Guidelines for Americans 2020–2025 state that decreasing weight “requires individuals to consume fewer calories from foods and beverages and expend more calories through physical activity.”
The authors of “The Carbohydrate-Insulin Model: A Physiological Perspective on the Obesity Pandemic,” a perspective published in The American Journal of Clinical Nutrition, argue that the energy balance model has fundamental flaws and that a different model, the carbohydrate-insulin model, better explains obesity and weight gain. Additionally, the carbohydrate-insulin paradigm paves the path for more effective, long-term weight loss techniques.
This weight-management strategy is based on the century-old energy balance theory, which posits that weight gain occurs when we consume more energy than we exert. In today’s society, surrounded by highly delicious, aggressively promoted, and inexpensive processed foods, it’s easy for people to consume more calories than they require, an imbalance aggravated further by today’s sedentary lives. According to this logic, obesity is being fuelled by excessive food and insufficient physical activity. On the other side, despite decades of public health messaging encouraging people to eat less and move more, obesity and obesity-related disorders have progressively increased.
According to lead author Dr. David Ludwig, an endocrinologist at Boston Children’s Hospital and a professor at Harvard Medical School, the energy balance model does not adequately explain the biological causes of weight gain: “During a growth spurt, for example, adolescents may increase their food intake by 1,000 calories per day. However, is it the adolescent’s overeating that causes the growth spurt, or is it the growth spurt that causes the adolescent to become hungry and overeat?”
In contrast to the energy balance concept, the carbohydrate-insulin model makes a bold assertion: obesity is not caused by excessive eating. Rather than that, the carbohydrate-insulin model attributes a significant portion of the responsibility for the present obesity pandemic to modern dietary patterns defined by an excess of foods with a high glycemic load, particularly processed, rapidly digestible carbs. These foods trigger hormonal responses that alter our metabolism fundamentally, resulting in fat storage, weight gain, and obesity.
When we consume highly processed carbs, our bodies secrete more insulin and less glucagon. This increases fat cell storage, leaving fewer calories available to fuel muscles and other metabolically active tissues. The brain feels that the body is not receiving enough energy, which results in hungry emotions. Additionally, metabolism may slow in an attempt by the body to conserve fuel. As a result, we tend to remain hungry while gaining additional fat.
To comprehend the obesity epidemic, we must evaluate not just how much we eat, but also how our hormones and metabolism are affected by the things we eat. The energy balance model, by asserting that all calories are equivalent to the body, omits this key component of the problem.
While the carbohydrate-insulin model is not new — it dates all the way back to the early 1900s — the perspective presented in the American Journal of Clinical Nutrition is the most comprehensive formulation of this model to date, authored by a team of 17 internationally renowned scientists, clinical researchers, and public health experts. They have compiled a synthesis of the expanding body of evidence supporting the carbohydrate-insulin paradigm. Additionally, the authors have identified a number of testable hypotheses that differentiate the two models, which will serve as a guide for future research.
Adopting the carbohydrate-insulin paradigm over the energy-balance model has far-reaching consequences for weight management and treatment of obesity. Rather than urging individuals to eat less, which is rarely effective in the long run, the carbohydrate-insulin model recommends a different way that places a greater emphasis on what we consume. According to Dr. Ludwig, “reduced consumption of readily digested carbs, which inundated the food supply during the low-fat diet era, decreases the underlying desire to store body fat.” As a result, individuals may be able to lose weight with less hunger and effort.”
The authors acknowledge that additional study is necessary to definitively test these models and, maybe, to develop new models that more closely match the findings. They advocate for constructive conversation and “collaborations among scientists with divergent perspectives on how to test predictions through rigorous and fair research.”