Why Overeating is not a major cause of obesity? A group of researchers argues that the main causes of the obesity epidemic are more related to the type of food we eat than to the amount of food we eat.
Summary : A group of researchers challenge the energy balance model by publishing a view on the cause of obesity. According to this model, the reason for weight gain is that people receive more energy than what they consume in the body. According to the authors, the definition of obesity as a disorder of energy balance, without considering the biological mechanisms underlying weight gain, repeats a principle of physics. The authors emphasize the carbohydrate-insulin model, which describes obesity as a metabolic disorder caused by what we eat, not the amount of food we eat.
- Public health statements encouraging people to eat less and exercise more have not been able to stop the rise in obesity and obesity-related diseases.
- The energy balance model, which states that weight gain is due to receiving more energy than energy consumed in the body, repeats one of the principles of physics without considering the biological mechanisms that control weight gain.
- According to the carbohydrate-insulin model, overeating does not cause obesity, but the process of gaining fat leads to overeating.
- The current epidemic of obesity is due in part to hormonal reactions to changes in food quality: in particular, foods with a high glycemic load that fundamentally alter metabolism.
- Focusing on what we eat is a better weight management strategy than consuming it.
Statistics from the US Centers for Disease Control and Prevention (CDC) show that obesity affects more than 40 percent of American adults and puts them at higher risk for heart disease, stroke, type 2 diabetes and some cancers.
According to the USDA’s 2025-2020 Food Guidelines (USDA), adults should reduce their calorie intake from foods and beverages and increase the amount of calories burned through physical activity to lose weight. This weight management approach is based on a century-old energy balance model that says that weight gain is due to the fact that you receive more energy than you consume.
In today’s world, which is surrounded by delicious, affordable food and cheap processed foods, it is easy for people to get more calories than they need, and this imbalance is exacerbated by today’s sedentary lifestyle. With this in mind, overeating combined with inadequate physical activity leads to the spread of obesity.
On the other hand, despite decades of public health messages encouraging people to eat less and exercise more, the rate of obesity and obesity-related illnesses has been steadily rising.
The authors of the article “Carbohydrate-Insulin Model: A Physiological Perspective on the Obesity Pandemic”, published in The American Journal of Clinical Nutrition , point out the basic drawbacks of the energy balance model. They argue that the alternative model, the “carbohydrate-insulin model,” better explains obesity and weight gain. In addition, the carbohydrate-insulin model refers to more sustainable and effective weight management strategies.
According to lead author David Ludwig, an endocrinologist at Boston Children’s Hospital and a professor at Harvard Medical School, the energy balance model does not help us understand the biological causes of weight gain: for example, during a growth spurt, adolescent food intake may be 1,000 calories. Increase per day. But does overeating cause a growth spurt or does a growth spurt cause adolescent hunger and overeating?
Unlike the energy balance model, the carbohydrate-insulin model claims that overeating is not the main cause of obesity. Instead, the carbohydrate-insulin model considers modern dietary patterns to be the main cause of the current obesity epidemic, which tends to overeat high-glycemic foods: especially processed carbohydrates, which are quickly digested. These foods trigger hormonal responses that fundamentally alter metabolism, leading to fat storage, weight gain, and obesity.
When we eat highly processed carbohydrates, the body increases insulin secretion and suppresses glucagon secretion. This signals fat cells to store more calories and leaves fewer calories available to provide the energy needed by muscles and other metabolically active tissues. The brain realizes that the body is not receiving enough energy, and this causes a feeling of hunger. In addition, metabolism may be reduced in the body’s attempt to save fuel; So, even when we are gaining extra fat, we usually feel hungry.
To understand the epidemic of obesity, we must not only consider the amount of food we eat but also how the foods we eat affect our metabolism and hormones. The energy balance model loses an important piece of the puzzle by claiming that all calories are the same for the body.
While the carbohydrate-insulin model is not new (dating back to the early 1900s), the most recently published view is the most comprehensive formulation of the model to date, and its authors are a group of 17 leading scientists, researchers, and experts.
The authors of the new article cite much evidence in support of the carbohydrate-insulin model. In addition, they have set out a set of testable hypotheses that distinguish the two models and that future research can be conducted on them.
Adopting the carbohydrate-insulin model instead of the energy balance model has major implications for weight management and obesity treatment. Instead of encouraging people to eat less (a strategy that usually does not work in the long run), the carbohydrate-insulin model suggests another way that relies more on the food we eat.
According to Dr. Ludwig, reducing the intake of fast-digesting carbohydrates that have flooded our food sources during a low-fat diet reduces the stimulus behind the body’s fat storage. As a result, people may lose weight with less hunger and less effort.
The authors acknowledge that more research is needed to definitively test both models, as well as to develop new models that are better consistent with the evidence. In this regard, they want a constructive discourse and the cooperation of scientists with different perspectives on accurate and unbiased research.
Source: AMERICAN SOCIETY FOR NUTRITION
