Obesity May Not Only Be Caused by Overeating, Carbohydrate-Insulin Model Can Better Determine Causes: Research

A recent study regarding nutrition suggests that overeating may not be the main cause of obesity. The research was carried out by 17 internationally prominent scientists in the field and was published on September 13 in The American Journal of Clinical Nutrition. The conclusion of the paper is backed by research that looks into the limitations and flaws of the energy balance model (EBM). EBM is, by far, the most common and dominant method of deciding the causal factors behind obesity. However, researchers suggest that a carbohydrate-insulin model (CIM) is a better way to define the causes of obesity.

EBM considers obesity as a disorder in energy balance but overlooks many biological mechanisms. According to the century-old model, weight gain is the direct result of consuming more energy than the body can expend. A sedentary lifestyle, which is the new normal these days due to the ongoing pandemic, results in lesser and lesser energy output. Therefore, the body starts to store energy in the form of fat.

EBM doesn't explain certain metabolic processes that are normal to the human body. The study states, “During the pubertal growth spurt, energy intake exceeds expenditure as body energy stores increase. Does increased consumption drive growth or does growth drive increased consumption?” Researchers say EBM completely disregards biological influences on the body's fat storage mechanism.

For a long time, overconsumption of high-calorie food was considered the sole cause of obesity. However, the recent study says, “Body weight is controlled by complex and interconnected systems involving multiple organs, hormones, and metabolic pathways.” That means numerous factors work towards weight gain or fat gain.

The alternative CIM model takes into account hormonal and metabolic factors when studying the causes of obesity. Like EBM, it also links food with fat gain. But it notes that weight gain is more about the composition of foods than their quantity being consumed. That's because different food components trigger different biological responses in the body.

CIM links fat deposition in the body to hormonal responses. When a high glycemic-load diet is consumed, the body's hormones signal the cells to store more calories. However, this fat storage mechanism deprives muscles and metabolism processes of their required energy. Hence, the body demands more food intake though it has consumed more calories than it is expending.

This research urges more studies to be done in this regard to ascertain the causes and implications of obesity.