Does Obesity Cause Long-Lasting Changes in the Brain?


According to research, obesity restricts the brain of a person from knowing that they are full. Moreover, the ability of the brain to detect nutrients in a certain way may be permanent, which explains why it is difficult to lose weight and maintain it.

WHO says that around four million people die because of obesity every year. The condition has reached the proportions of epidemics. In fact, more people are obese than skinny in the world except in Asia and Saharan Africa.

How the body responds to nutrient intake is well understood and how it plays a role in eating behaviour. Although there isn’t much info about the signalling. Previous research into post-ingestive nutrient signals to the brain and eating regulation in mice has shown impaired responses to signals associated with obesity and other pathological eating behaviours. However, there is barely any information about this in humans.

“Lean” Criteria

In the most recent study, a team of researchers infused glucose or fat into the stomachs of twenty-eight people directly. They were all under the criteria of “lean” with a BMI of 25 and lower. Moreover, thirty people with a BMI of 30 or higher were given either glucose, fat, or water randomly. Water served as a control in the study.

They used functional magnetic resonance imaging for assessing the brain activity of the participants. A decrease in the activity was seen in the lean participants. However, no changes were evident in the classified obese participants.

Mireille Serlie, senior author of the study said,

This was surprising

We thought there would be different responses between lean people and people with obesity, but we didn’t expect this lack of changes in brain activity in people with obesity.

The team also examined the striatum, which regulates the body’s desire to eat and find food actively. There was a decrease in activity in lean people in two parts of the striatum after glucose and fat infusions. However, only one area of the striatum was affected by these changes. Moreover, there were no changes in the activity because of fat.


The results depict that glucose releases dopamine in both participants but fat only caused dopamine release in lean participants. Even after re-examination in participants who followed 12-week dietary changes did not show any meaningful results in the brain’s response despite 10% body weight loss.


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