The cause of obesity has always been considered to be overeating. It's just common sense, right? Obesity and overeating have been studied for at least a hundred years, which led to the energy balance model (EBM). This model states that when more calories are ingested than the body expends in activity, the excess is stored in fat cells, and that's why you're fat. But some things about this assumption don't quite add up. Why are so many people able to balance that energy intake so easily, while others struggle all their lives? A new study published Monday takes a closer look at the biological functions of fat development and the importance of the carbohydrate-insulin model, or CIM.
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 to fundamental flaws in the energy balance model, arguing that an alternate model, the carbohydrate-insulin model, better explains obesity and weight gain. Moreover, the carbohydrate-insulin model points the way to more effective, long-lasting weight management strategies.
According to lead author Dr. David Ludwig, Endocrinologist at Boston Children’s Hospital and Professor at Harvard Medical School, the energy balance model doesn’t 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. But does their overeating cause the growth spurt or does the growth spurt cause the adolescent to get hungry and overeat?”
In contrast to the energy balance model, the carbohydrate-insulin model makes a bold claim: overeating isn’t the main cause of obesity. Instead, the carbohydrate-insulin 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. These foods cause hormonal responses that fundamentally change our metabolism, driving fat storage, weight gain, and obesity.
So where does that take us? Further research is needed, as you have guessed, to test the two models against each other. If the CIM model is more useful, we could change the way our food is processed, and it might go a long way toward changing the perception of obesity as a moral failure. Read about the research at SciTech Daily.
One of the study's authors also takes us through the history of obesity science and how the EBM model kept scientists from exploring other reasons for the rise of obesity in this essay.
(Image credit: Renée Gordon)
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