Scientists are comparing studies of drug addiction and overeating - and they're finding more in common with the two afflictions than previously thought. Ralph DiLeone, a brain scientist at Yale University, says "The motivation to take cocaine in the case of a drug addict is probably engaging similar circuits that the motivation to eat is in a hungry person." They believe the food-drug connection occurs because the brain contains "special pathways that make us feel good when we eat, and really good when we eat sweet or fatty foods with lots of calories." These 'special pathways' exist to aid in our survival as a built in instinct to nudge early humans toward eating foods high in calories.
Obviously, foods are not quite as addicting as most drugs, but an important take-away of the study is that our long-term eating habits can alter our daily eating behaviors in a lifelong fashion. Teresa Reyes, a research assistant professor in the Department of Pharmacology at the University of Pennsylvania, has run a number of experiments measuring the food "reward circuitry" in obese mice. She says, "What we found is that in animals that were obese, there were really dramatic changes in these areas of the brain that participate in telling us how rewarding food is. The changes made these areas less responsive to fatty foods, so an obese mouse would have to eat more fat than a typical mouse to get the same amount of pleasure."
Even after the mice were put back on a normal diet, things didn't always go back to normal. Reyes thinks this might explain why obese children often carry their weight into adulthood.
"So it is similar to what happens in cases of chronic drug abuse," Reyes says. "The reward circuitry changes in a similar way, and that promotes the seeking of that drug, or in our case, in seeking palatable food."