If you have a tough time saying no to free donuts, or taking an extra slice of pizza at dinner, a new study suggests you can blame your brain for the cravings.
According to a new study from Yale University, people's brains have a more rewarding experience when we consume foods high in carbohydrates and fats. Dana Small, a professor of psychiatry at Yale and the senior author on the study said the findings from the study provide the first evidence that the rewarding effects of fat and carbohydrates interact to increase to increase our desire for the junk food.
"Our study shows that when the signals are combined, they make foods more reinforcing," said Small.
To test this, researchers gave study participants three different types of foods. Those containing mostly fats, mostly carbs, or a combination of the two. Participants were asked to pay for the foods in an auction-like exercise while their brains were being scanned by functional magnetic resonance imaging (fMRI).
Turns out, people were more willing to pay more for the foods that combined the fats and carbs. That correlated with activity measured by researchers in the brain's dorsal striatum and mediodorsal thalamus, two areas that are key for how our brains assess rewards.
That means people can end up eating more than we mean to, leading to inadvertent weight gain.
The study points out that most snack foods on the market today average around 24% fat and 57% carbohydrates, far beyond anything found in nature.
"In the modern food environment that is rife with processed foods high in fat and carbohydrate like donuts, French fries, chocolate bars, and potato chips, this reward potentiation may backfire to promote overeating and obesity,” said Small.