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Indulging in a junk food binge can have lasting effects on your brain, even after you return to your usual eating habits. A recent study found that five days of overeating high-calorie, nutrient-poor foods temporarily boosted brain insulin sensitivity but caused a drop in responsiveness once participants switched back to a healthier diet.

Researchers assigned 29 healthy-weight men, ages 19 to 27, to one of two groups: One followed a junk food diet for five days, while the other stuck to their regular eating habits. They measured participants' brain insulin activity through imaging techniques and insulin administration before and after the binge.

At the peak of the junk food binge, researchers observed heightened insulin activity in key brain regions. However, just one week after returning to their usual diet, participants who had overindulged experienced lower brain insulin sensitivity, particularly in areas associated with memory and food-related reward, such as the hippocampus and fusiform gyrus. Interestingly, while the junk food group showed increased liver fat, there were no noticeable changes in weight or peripheral insulin sensitivity.

These findings suggest that the effects of overeating go beyond immediate metabolic changes, potentially contributing to cognitive decline and influencing eating behaviors over time. They also underscore how even a brief junk food binge can disrupt insulin function in the brain, impairing areas critical to memory and decision-making. Behavioral strategies like mindfulness can help curb overeating. Learn more in this clip featuring Dr. Ashley Mason.