Obese adults may be more susceptible to environmental food cues than lean adults due to differences in brain chemistry that make eating more habitual and less rewarding, according a new study. Findings of the study are published in Molecular Psychiatry.
Researchers conducted a study in 43 men and women with varying amounts of body fat. Study subjects followed the same eating, sleeping, and activity schedule. A questionnaire was used to determine their tendencies to overeat in response to an environmental trigger. PET scans were also used to evaluate the site in the brain where dopamine was able to act.
The obese participants tended to have greater dopamine activity in the habit-forming region of the brain than their lean counterparts, and less activity in the region controlling reward. This might help explain how the obese are more drawn to overeat in response to food triggers and simultaneously make food less rewarding to them.
A causal relationship between habit formation, reward, dopamine activity, eating behavior, and obesity was not established. Researchers note further research will study dopamine activity and eating behavior in people over time with changing diets, physical activity, and weight.
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