Snacks high in sugar and fat are great for an occasional treat, but when enjoyed daily for several weeks they can rewire the brain and trigger a shift in eating preferences away from low-fat food.
An international research study published March 22 in Cell Metabolism found that eating just one high-fat and high-sugar serving of yogurt every day over eight weeks sensitized brain reward circuits to food cues while simultaneously decreasing liking for low-fat food.
The research team, which included Dana M. Small, PhD, professor of psychiatry and of psychology at Yale School of Medicine, observed the effect despite the fact that the participants were of healthy weight and did not gain weight or show any signs of changes in metabolic health. Further, brain reward circuits also became primed to learn about other types of reward.
The study shows that mere exposure to unhealthy food is sufficient to cause changes in the way the brain responds to food.
“Adding one unhealthy snack per day to your diet changes the way your brain learns about rewards,” said Small, the paper’s senior author. “More importantly, it does so in a way that could promote overeating. This means that even in individuals with no intrinsic or genetic risk for obesity, exposure to an unhealthy diet can produce that risk.”
The scientists tested their research on 49 people with healthy body mass indexes. Twenty-six people were given a high fat and high sugar yogurt treat daily, while 23 were given a low fat, low sugar alternative. Over time, those who consumed the higher fat treat saw their preference for a low-fat food decrease.
Exposure to food high in fat and sugar plays a critical role in altering brain responses to anticipation and consumption of highly palatable, energy-dense food, the researchers concluded.
“Taken together, repeated consumption of high-fat and high-sugar (food) relative to isocaloric low-fat and low-sugar food and in the absence of changes in body weight or metabolic state can rewire brain circuits and thereby induce neurobehavioral adaptations,” the researchers wrote. “Hence, changing the food environment and reducing the availability of energy dense high-fat/high-sugar food items is pivotal to combating the obesity pandemic.”