Why do most of us crave junk food, fried foods, salty snacks and candy when we know they are not good for us at best and can lead to serious health problems at worst? It’s because after consuming those foods, our brains get “rewired” to prefer them over healthier choices, according to a group of international scientists.
Researchers at the Max Planck Institute for Metabolism Research in Germany, in collaboration with Yale University, recently conducted a study they say shows that foods with a high fat and sugar content actually change the brain … and if we regularly eat even small amounts of them, our brains learn to prefer them in the future.
Their study included two groups of healthy, normal-weight volunteers. The first – the test group – received a high-fat, high-sugar pudding snack in addition to their regular diet every day for eight weeks. The second control group received a snack that contained the same number of calories, but less fat and sugar.
By the time the experiment ended, the group receiving the high-fat, high-sugar snacks not only expressed a greater preference for these foods on subjective surveys; actual measurements of their brains’ neural responses to anticipating their daily snack were also significantly stronger than those of volunteers in the control group. These changes held true independently of changes in body weight and other metabolic parameters, which the researchers say indicates a direct and learned effect of high-fat, high-sugar foods on the brain.
While those in the test group did not gain more weight, and their blood cholesterol did not change, compared to those in the control group during the experiment, their preference for foods containing more fat and sugar was likely to continue after it ended, according to study leader and Max Planck scientist Marc Tittgemeyer. “After all, the whole point of learning is that once you learn something … You don’t forget it so quickly,” Tittgemeyer said. The study was published in the journal Cell Metabolism.