In the United States, more than 40% of adults have obesity, putting them at risk of developing heart disease, type 2 diabetes, stroke, and certain types of cancer, according to the Centers for Disease Control and Prevention (CDC).

The Dietary Guidelines for Americans tell us that losing weight “requires adults to reduce the number of calories they get from foods and beverages and increase the amount expended through physical activity.”

We often think that overeating is one of the major causes of obesity. We are surrounded by highly palatable and cheap processed foods, which makes us eat more calories than we need, a kind of imbalance that is further exacerbated by physical inactivity.

However, a new study, published in The American Journal of Clinical Nutrition, says that overeating is not the main cause of obesity, according to Science Daily.

The study pointed out that the carbohydrate-insulin model better explains obesity and weight gain. In addition, the model suggests a way to more effective, long-lasting weight management strategies.

Lead author Dr. David Ludwig of Harvard Medical School said the conventional energy balance model does not help us understand the biological causes of weight gain.

“During a growth spurt, for instance, adolescents may increase food intake by 1,000 calories a day,” he said, “but does their overeating cause the growth spurt or does the growth spurt cause the adolescent to get hungry and overeat?”

The carbohydrate-insulin model claims that overeating is not the main cause of obesity. Instead, the model “lays much of the blame for the current obesity epidemic on modern dietary patterns characterized by excessive consumption of foods with a high glycemic load: in particular, processed, rapidly digestible carbohydrates,” per Science Daily.

The highly processed foods cause hormonal responses that change our metabolism, causing fat storage, weight gain, and obesity.

Upon eating highly processed carbohydrates, our body increases insulin secretion and suppresses glucagon secretion, which eventually signals fat cells to store more calories and leaves fewer calories for muscles and other metabolic activities.

It is important to understand how much we are eating and how the foods we eat affect our hormones and metabolism.

Adopting the carbohydrate-insulin model instead of the energy-balance model has radical implications for weight management and obesity treatment.

The carbohydrate-insulin model focuses more on what we eat.

Dr. Ludwig said, “Reducing consumption of the rapidly digestible carbohydrates that flooded the food supply during the low-fat diet era lessens the underlying drive to store body fat. As a result, people may lose weight with less hunger and struggle.”

However, the researchers said further studies are needed to conclusively test both models and, perhaps, to generate new models that better fit the evidence.

They have even called for constructive discourse and “collaborations among scientists with diverse viewpoints to test predictions in rigorous and unbiased research.” The article appeared in Science Daily.