科学美国人60秒:Junk Diet Rewires Rat Brains

We know junk food can change the way bodies are shaped. Now, a study finds that those irresistible sweet and salty concoctions may also change the way brains are wired—at least in rats.

Researchers divided rats into two groups—one labeled Cafeteria, the other called Chow. Both groups got a typical rat food diet, but the Cafeteria rats also got a bonus: meat pies, cakes and cookies. 

Both rat groups gained weight. But the Cafeteria rats gained significantly more than the Chows did—nearly half a pound more, which is a big body burden for a rat. But more important, over two weeks time the Cafeteria rats seemed to care less and less about even seeking out a balanced diet. This new behavior endured even after the rats were returned to their more healthy fare. The study is in the journal Frontiers in Psychology. [Amy C. Reichelt, Margaret J. Morris and R.F. Westbrook, Cafeteria diet impairs expression of sensory-specific satiety and stimulus-outcome learning]

The researchers think junk-food diets cause lasting changes in the rewards circuits part of the brain—which plays a big role in decision-making. So if you’re a regular cookie eater and the next time you mindlessly reach for a cookie you wonder why you can’t help yourself—well, it could be because you’re not in charge, your rewired brain is.

—Erika Beras 


(The above text is a transcript of this podcast)