A new study reveals the effects of obesity on the brain.
- Obesity decreases the brain’s ability to detect satiety.
- Even after dieting, this dysfunction does not recover.
- Today, 17% of French people are obese (including 6% of children aged 8 to 17).
A new study published in Nature shows that obesity decreases the brain’s ability to detect satiety.
Decreased brain activity in obese people
To achieve these results, a team of researchers from the Netherlands and the United States conducted a study on 28 lean people and 30 obese people. Participants received infusions of glucose, fat, or water.
The researchers then used functional magnetic resonance imaging (fMRI) to assess participants’ brain activity. The results showed that the obese participants showed no change in their brain activity following the infusions, unlike people considered lean who showed signs of reduced activity in different regions of their brains.
This altered brain activity may explain why obese people have trouble feeling full after a meal, contributing to their tendency to overeat.
An impact on the brain’s ability to regulate appetite
The researchers also looked at the participants’ striatum, a region of the brain that regulates the body’s desire to eat. Using single-photon emission computed tomography (SPECT), they found that lean people had reduced activity in two parts of their striatum after receiving an infusion of glucose and fat. In contrast, only glucose infusions caused activity changes in the brains of obese participants.
This altered activity in the striatum may also contribute to increased appetite in obese people, causing them to seek more food.
Diet does not restore altered brain responses
Then, participants with obesity followed a 12-week weight loss program. Those who managed to lose 10% of their body weight were then re-examined. The results then showed no significant change in the brain’s responses to the infusion.
This finding suggests that diet-induced weight loss does not restore altered brain responses in obese people. It is therefore crucial to further investigate the brain mechanisms involved in appetite regulation in order to develop more effective approaches to prevent and treat obesity.
Obesity figures in France
In 2020, nearly one in two French people (47.3%) was overweight and/or obese, according to figures from a new Odoxa survey for The Obesity League. And it is obesity that is progressing the most, it has doubled since 1997. Today, 17% of French people are obese (including 6% of children aged 8 to 17).
Massive obesity has practically doubled in a decade, going from 1.1% in 2009 to 2% in 2020, and now concerns more than one million French people.