Increased Weight Reduces The Brain's Response To Tasty Food.
Most common man doubtlessly find drinking a milkshake a pleasurable experience, sometimes extremely so. But apparently that's less apt to be the case among those who are overweight or obese.
Overeating, it seems, dims the neurological answer to the consumption of yummy foods such as milkshakes, a new study suggests. That effect is generated in the caudate nucleus of the brain, a region involved with reward.
Researchers using going magnetic resonance imaging (fMRI) found that that overweight and obese people showed less activity in this brain precinct when drinking a milkshake than did normal-weight people.
"The higher your BMI [body mass index], the moderate your caudate response when you eat a milkshake," said study lead author Dana Small, an ally professor of psychiatry at Yale and an associate fellow at the university's John B. Pierce Laboratory.
The execute was especially strong in adults who had a particular variant of the taqIA A1 gene, which has been linked to a heightened jeopardize of obesity. In them the decreased brain response to the milkshake was very pronounced. About a third of Americans have the variant.
The findings were to have been presented earlier this week at an American College of Neuropsychopharmacology encounter in Miami.
Just what this says about why multitude overeat or why dieters say it's so hard to by highly rewarding foods is not entirely clear. But the researchers have some theories.
When asked how pleasant they found the milkshake, overweight and obese participants in the study responded in ways that did not differ much from those of normal-weight participants, suggesting that the key is not that obese people don't enjoy milkshakes any more or less.
And when they did brain scans in children at gamble for obesity because both parents were obese, the researchers found the opposite of what they found in overweight adults.
Children at jeopardy of obesity actually had an increased caudate response to milkshake consumption, compared with kids not considered at hazard for obesity because they had lean parents.
What that suggests, the researchers said, is that the caudate response decreases as a outcome of overeating through the lifespan.
"The decrease in caudate response doesn't precede weight gain, it follows it. That suggests the decreased caudate reaction is a consequence, rather than a cause, of overeating."
Studies in rats have had comparable results, said Paul Kenny, an associate professor in the behavioral and molecular neuroscience lab at the Scripps Research Institute in Jupiter, Fla.