Obesity Due to a Failing Metabolic Mechanism
In obese people, a mechanism that regulates energy storage and expenditure would be failing and would lead to excess weight.
No, obesity is not only due to excessive dietary intakes compared to energy expenditure. Researchers in the Metabolic Diseases and Obesity Program have come to understand that a failing mechanism in obesity reduces the energy expenditure of those affected.
The study in Cell Metabolism tells us that the brain of a healthy individual detects differences in levels of insulin in the blood and acts accordingly. After a meal, it is very high because there is a lot of glucose in the blood and the brain deduces that it must activate the energy expenditure. Since the body has just been fed, it does not need to store calories. This phenomenon is called fat browning. Adipocytes, the fat cells, pass from the white fat, which stores energy, to the brown fat that destocks it and burns it.
On the contrary, after a fast the body must store energy: the brain detects a low level of insulin, it then asks the brown fats to convert into white fats to promote the storage of calories.
A Mechanism always in the “ON” position
This mechanism helps to prevent excess fat but also shortfalls, aiming for stability over time. The ability of the brain to feel the level of insulin and coordinate its orders to get the correct response from the fat cells is controlled by a tipping mechanism that starts after a fast and stops at a meal. In obese people, the brain fails to stop the mechanism and the tilting does not happen. As a result, a meal does not trigger an increase in energy consumption: calories ingested are stored more and the person gains weight.
The challenge for researchers now is to find a way to put the mechanism on off to resume energy expenditure and lead to weight loss. This would treat obesity that affects more and more people in the world.