A collaborative study by Amsterdam UMC and Yale University has uncovered that obesity correlates with a reduced brain response to nutrients, which persists despite weight loss.
This diminished response, characterized by lower dopamine release and decreased nutrient-sensing activity, likely contributes to the challenges individuals face in maintaining weight loss.
Published in Nature Metabolism, the study reveals that individuals with obesity exhibit diminished brain responses to specific nutrients that do not improve following weight loss.
Key findings from the research highlight significant differences in dopamine release and neural activity in brain regions crucial for food motivation between individuals with obesity and those with a healthy body weight.
Lead researcher Mireille Serlie, Professor of Endocrinology at Amsterdam UMC, explains, “Our findings suggest that persistent adaptations occur in the brains of individuals with obesity, potentially influencing eating behavior.
We observed reduced dopamine release in brain areas linked to the rewarding aspects of food intake compared to those with a healthy weight.
Additionally, individuals with obesity showed diminished responsiveness in brain activity when nutrients were infused into the stomach.
These observations suggest that the ability to sense nutrients in the gut and stomach, or the processing of nutritional signals, is impaired in obesity, which could significantly impact food intake.”
The study underscores the intricate interplay between metabolic signals, neuronal communication, and eating behavior regulation involving the brain, gut, and blood nutritional cues.
While animal models have provided insights into these mechanisms, understanding these processes in humans has been challenging due to limitations in clinical experimental setups.
To bridge this gap, Serlie and her team devised a controlled trial involving 30 participants with a healthy body weight and 30 individuals with obesity.
They administered specific nutrient infusions directly into the stomach while monitoring brain activity using MRI scans and dopamine release through SPECT scans.
Results demonstrated distinct patterns of brain activity and dopamine release in response to nutrient infusion among participants with a healthy body weight, contrasting with significantly blunted responses in those with obesity.
Moreover, even after achieving a 10% reduction in body weight following a 12-week diet program, individuals with obesity did not exhibit restored brain responses to nutrients, indicating enduring brain adaptations associated with obesity.
“The persistence of altered brain responses post-weight loss may elucidate why many individuals regain weight following initial successful weight loss,” Serlie concludes.
This study highlights the complex neurological underpinnings of obesity and underscores the need for further research into sustainable interventions that address these physiological adaptations.
