WASHINGTON – Drink a milkshake and the pleasure center in your brain gets a hit of happy – unless you’re overweight.
It sounds counterintuitive. But scientists who watched young women savor milkshakes inside a brain scanner concluded that when the brain doesn’t sense enough gratification from food, people may overeat to compensate.
The small but first-of-a-kind study even could predict who would pile on pounds during the next year: Those who harbored a gene that made their brain’s yum factor even more sluggish.
“The more blunted your response to the milkshake taste, the more likely you are to gain weight,” said Dr. Eric Stice, a senior scientist at the Oregon Research Institute who led the work, published in today’s edition of the journal Science.
Diet and exercise are the main factors in whether someone is overweight. But scientists have long known that genetics also play a role in obesity – and one culprit is thought to be dopamine, the brain chemical that’s key to sensing pleasure.
Dr. Nora Volkow of the National Institutes of Health, a dopamine specialist who has long studied the obesity link, notes that “dopamine is not just about pleasure.” It also plays a role in conditioning and the ability to control impulses.
She wonders if instead of overeating to compensate for the lack of pleasure – Stice’s conclusion – the study might show that people with malfunctioning dopamine eat because they’re impulsive.
If doctors could determine who carries the at-risk gene, children especially could be steered toward “recreational sports or other things that give them satisfaction and pleasure and dopamine that aren’t food,” said Stice.