Researchers from Amsterdam UMC and Yale University have discovered that obesity leads to persistent changes in brain responses to nutrients, which are not restored even after weight loss.
Their findings, published in Nature Metabolism, could provide vital insight into why many people struggle to maintain weight loss after initially successful efforts.
Dopamine Release and Obesity
The study found that individuals with obesity released less dopamine in a brain region critical for the motivational aspect of food intake, compared to those with a healthy body weight.
Dopamine is a neurotransmitter involved in the rewarding feelings associated with eating.
“Those with obesity also showed reduced responsivity in brain activity upon infusion of nutrients into the stomach,” explained lead researcher Mireille Serlie, Professor of Endocrinology at Amsterdam UMC.
“Overall, these findings suggest that sensing of nutrients in the stomach and gut and/or of nutritional signals is reduced in obesity, and this might have profound consequences for food intake.”
The Study Design
Understanding the relationship between the brain, food intake, and obesity is complicated due to the intricate interplay of metabolic and neuronal signals across the brain and various organs, including the gut.
These networks trigger sensations of hunger and satiation, regulate food intake, and influence the motivation to seek food.
To study these mechanisms in humans, Serlie and her team designed a controlled trial involving 30 individuals with healthy body weight and 30 with obesity.
The participants were infused with specific nutrients directly into their stomachs, while their brain activity was monitored using MRI scans and dopamine release was tracked with SPECT scans.
Findings and Implications
The researchers found that healthy-weight participants showed particular patterns of brain activity and dopamine release following nutrient infusion.
In contrast, these responses were considerably diminished in participants with obesity.
Even after a 10% body weight loss following a 12-week diet, these brain responses were not restored in the obese participants.
This suggests that obesity leads to long-lasting brain adaptations, which persist even after weight loss.
“The fact that these responses in the brain are not restored after weight loss may explain why most people regain weight after initially successful weight loss,” concluded Serlie.
If you care about weight management, please read studies about diets that could boost your gut health and weight loss, and 10 small changes you can make today to prevent weight gain.
For more information about obesity, please see recent studies about low-carb keto diet could manage obesity effectively and results showing popular weight loss diet linked to heart disease and cancer.
The study was published in Nature Metabolism.
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