Brain’s Food Smell Circuitry Might Cause Overeating

A miscommunication between brain regions may lead some people to eat too much.

No doubt, the smell of fresh-baked bread is appetizing when you’re hungry. At the same time, it can be less alluring if you’re already feeling stuffed. That’s due to the interaction between two different parts of the brain involving sense of smell and behavior motivation, a study out of the Northwestern University Feinberg School of Medicine, in Chicago, reveals. And, according to the findings published in Journal of Neuroscience, it could be the reason why some people can or can’t easily stop eating when they’re stuffed. For the first time in humans, the researchers mapped the strength of the circuit between two brain regions:

1. The olfactory tubercule, which is tied to the sense of smell and the brain’s reward system.
2. The periaqueductal gray; an area of the brain that contributes to motivating behavior in response to negative feelings like pain and threat, and is also potentially involved in the suppression of eating.

People with weak or disrupted circuits connecting these areas could keep eating even when they aren’t hungry, because food is still rewarding to them even when they feel full. Indeed, when the structural connection between these two brain regions is weaker, a person’s BMI is higher, on average. On the flipside, healthy brain connections between these regions could better regulate eating behavior by sending messages telling the person that eating doesn’t feel good when they’re full. The scientists believe that determining how these basic processes work in the brain is an important prerequisite to future work that could lead to treatments for overeating and excess calorie consumption that contributes to obesity.