A study conducted on three groups of lab rats has provided some interesting insights into what might possibly drive humans to binge on fatty, high calorie food. In a study published in the journal Nature Neuroscience, researchers studied the rats for 40 days. One group was fed "regular" rat food (whatever that means); another got bacon, sausage, cheesecake, etc., for just one hour each day; and the third group received access to the unhealthy foods for up to 23 hours a day. The third group's unlimited binging changed their brains.

Overeating caused the levels of a certain dopamine receptor in the brains of the obese rats to drop; this same pattern is observed in human drug addicts. Researchers monitoring brain electrodes found that the rats in the third group developed a tolerance to the pleasure the food gave them and had to eat more to get "high," just like that greasy hipster jonesing for one more bump outside the bathrooms at Union Pool. Dr.Gene-Jack Wang, M.D., tells CNN he's not surprised to see junk food elicit this addictive response because "we make our food very similar to cocaine now."

Just as coca leaves are processed to make the drug reach the brain more efficiently, "our ancestors ate whole grains, but we're eating white bread. American Indians ate corn; we eat corn syrup... like a drug abuser [uses drugs]," says Wang. According to CNN, "When researchers applied an electric shock to the rats' feet in the presence of the food, the rats in the first two groups were frightened away from eating." But not the fat rats in group three! "Their attention was solely focused on consuming food," observes Paul J. Kenny, Ph.D., a co-author of the report. Once it hits your lips, it's so good!