one reason overweight people eat more than they need to

The is a new report out that says that scientists have discovered one reason overweight people eat more than they need to .The report says that Obese people don't appear to get as much pleasure as they expect from tasty treats.

The report, published in the Oct. 17 issue of the journal Science, involves some high-tech brain scans, some fancy genetic tests —and some chocolate milkshakes.

What makes chocolate just the thing to shine a light on the brain's "reward system" . Chocolate milkshakes are ideal for the purpose, because the yummy flavor can be squirted through a straw while volunteers' heads are clamped into an MRI scanner. That yields images of brain blood flow, identifying which parts of the brain are responding to a stimulus — in this case, the taste of the milkshake.

The researchers found three important things:

• • When obese women ate food, they had a "blunted" dopamine response in the brain's reward center compared with lean people.
• • This low response was amplified among women who had the gene variant that results in fewer dopamine receptors.
• • A year after the brain scans, women with the gene variant had put on more weight than women without the gene.