Decreasing Food increases "Pleasure" Chemical

New research provides evidence that the brain's "reward" chemical, dopamine, is linked with obesity, and that restricting food can increase dopamine levels - known as a reward or pleasure chemical.

At this stage the brain-imaging study has only tested rats, but scientists are confident that the findings will also apply to people. The researchers found:

• Genetically obese rats had lower levels of dopamine D2 receptors than lean rats
• Restricting food intake can increase the number of D2 receptors, partially attenuating a normal decline associated with aging.

According to Brookhaven neuroscientist Panayotis (Peter) Thanos, lead author of the current study, published online in the journal Synapse on October 25, 2007

This research corroborates brain-imaging studies conducted at Brookhaven that found decreased levels of dopamine D2 receptors in obese people compared with normal-weight people.

Because food intake can have such a dramatic effect on dopamine receptor levels, this study also provides further evidence for the interplay of genetic factors with the environment in the development of obesity in our society.

What isn't yet clear, is whether the lower levels of dopamine are a cause of obesity, or occur as a result of overeating. Thanos hopes that further research will determine whether obesity is a result of biology or bad dietary choices. Thanos also raises the possibility that adjusting dopamine levels through medication or diet may aid weight loss efforts.