Compulsive Eating Resembles Addiction

Overeating appears to be driven by the same brain changes that lead to drug addiction, according to newly published research (Nat. Neurosci., DOI: 10.1038/nn.2519). Neuroscientists Paul M. Johnson and Paul J. Kenny of Scripps Research Institute in Jupiter, Fla., gave some rats palatable high-fat, high-calorie food. The rats ingested twice the calories of normal rats. They lost control over their eating behavior, continuing to overeat even when faced with the threat of electric shocks. When the researchers tried to switch them back to a normal, nutritious diet, the rats refused to eat it. The researchers say that the tasty food overstimulates the reward circuit in a rat’s brain, and the brain adapts by decreasing the number of type 2 dopamine receptors in that circuit—just as it does in cocaine or heroin addicts. As a result, the rat needs constant stimulation from tasty food to avoid what the authors call “a persistent state of negative reward.” They suggest that medications developed to treat addiction could also be used to treat overeaters.