Junk food works like crack, at least that's what a recent study by scientists at Scripps Florida suggests.
The scientists fed groups of rats different types of food. One group was given a healthy diet. Another group was given a healthy diet with unlimited access to junk food. "We basically bought all of the stuff that people really like -- Ding-Dongs, cheesecake, bacon, sausage, the stuff that you enjoy, but you really shouldn't eat too often," researcher Paul Kenny told Reuters.
The rats given the junk food option consumed twice as many calories.They became inactive. Even after a light went off warning them of a coming electrical shock if they ate more, they continued to gorge. (The rats eating a healthy diet stopped eating at the light.) When the rats were cut off from the junk food after two weeks, they refused to eat anything.
When the rats ate junk food, their brains released dopamine, a pleasure inducing chemical. The stimulation led to a desire to eat more junk food. As the rats ate more and more junk food, the receptor that responds to dopamine became desensitized. The rats had to eat increasing amounts of food to trigger the same pleasure response. The receptor that became desensitized is the same one that responds to other pleasurable stimuli, like sex and drugs.
What happens in addiction is lethally simple, Kenny explained in a press release. The reward pathways in the brain have been so overstimulated that the system basically turns on itself, adapting to the new reality of addiction, whether its cocaine or cupcakes.
"These findings confirm what we and many others have suspected," Kenny said, "that overconsumption of highly pleasurable food triggers addiction-like neuroadaptive responses in brain reward circuitries, driving the development of compulsive eating. Common mechanisms may therefore underlie obesity and drug addiction."