French Researchers Shed Light on the Mechanisms Behind the Feeling of Satiety

French researchers in a new study demystified the mechanisms behind the feeling of satiety that regulates our appetite. During a meal, an increase in blood sugar levels causes nerve cells to change shape.

Obesity at Critical Levels

Two billion people in the world are overweight (BMI between 25 and 30) or obese (BMI of 30 or more). The recent estimates suggest that 25% of the adult population is obese. The causes behind this disease are multifactorial. Genetics, hormonal disorders, endocrine disrupters, mental and social fragility, sedentary lifestyles, environmental pollution or low income are some of the causes. In obese individuals, neuronal circuits that control the feeling of hunger and satiety in the brain and thus maintain a balance between energy intake and consumption could also be deregulated, according to some researchers. French scientists understood the mechanisms behind the feeling of satiety as a cascade of reactions triggered by an increase in blood sugar levels. The results of their study, which was carried out on rats, were published in Cell Reports magazine.

Here, researchers from The French National Center for Scientific Research (CNRS), National Research Institute for Agriculture (INRAE), University of Burgundy, University of Paris, INSERM and University of Luxembourg were interested in the POMC neurons of the hypothalamus at the base of the brain, which are known to limit food intake. They receive a large number of nerve endings from other parts of the brain and their connections are very flexible. This allows them to make and break these connections very quickly in response to hormonal fluctuations. By working with mice, researchers have discovered that after a balanced meal, the animals’ hormone cycle has not been altered.

On the other hand, other nerve cells associated with POMC neurons, so-called astrocytes, alter their shape. Normally, they closely overlap the POMC neurons and act a bit like brake pads, limiting their activity explains the CNRS in a press release. However, after a meal, the blood sugar level, or glycemia, increases temporarily. This signal is then perceived by the astrocytes, which retract in less than an hour. When the brake is released, the POMC neurons are activated which triggers the sensation of satiety.

The Secret of Lipids and Sweeteners

A meal rich in fat, however, does not cause this change. That is why scientists now want to find out whether lipids trigger satiety through a different circuit. It also remains to be seen whether sweeteners have the same effects as regular sugars or are “real baits for the brain that only provide the addictive sweet sensation without cutting off hunger,” says the CNRS.

Although the plasticity of these neural circuits might be altered in obese people and as such many of them do not receive the signals that cause satiety, which causes them to overeat.

To avoid this, all you have to do is change your habits. First, try not to eat for four hours to get very hungry. If you never feel hungry, it is possible that are eating “early” to overcome your fear of deprivation. If you are hungry all the time, you may be confusing physiological hunger with psychological hunger.

Eat Slowly and Calmly to Feel Satiety

Therefore, wait until you are really hungry and once you have food on hand, do not rush! Chewing your food about twelve times before swallowing it allows the signals to reach the areas of the brain that rewards you. If you swallow your food right away, your brain doesn’t get the information, and the feeling of satiety takes longer to arrive.

It is also recommended that you eat in a quiet environment. Avoid eating while walking, watching TV or answering emails, as this will distort your relationship with the food. After all, if you do something else at the same time, you forget you are eating, and this happens automatically.