It happens to the best of us: You walk into the supermarket intent on filling your cart with nothing but healthy foods, only to be blindsided by the oh-so-enticing smell wafting from the bakery aisle. It turns out you can blame your hormones for why you’re standing with muffins at the checkout line, according to re┬¡search in Cell Reports.
In the study, scientists from the Montreal Neurological Institute and Hospital at McGill University injected 38 participants with ghrelin, a gut hormone that encourages us to eat. Ghrelin also drives up production of dopamine, a neurotransmitter involved in reward response. Researchers then exposed the volunteers to a variety of odors while showing them images of various objects, so that they eventually associated certain images with certain odors. The experiment found that in people injected with ghrelin, activity increased in regions of the brain involved in dopamine response, but only in response to the images associated with appetizing food smells. A dose of ghrelin also increased the perceived pleasantness of food-associated images. This suggests that ghrelin may be a major factor in why some people get more stimulated by food cues such as odors and advertising and, in turn, may struggle to maintain a healthy diet.