Brain Triggers High-Calorie Cravings in Obese

LOS ANGELESLow blood sugar influences the bodys ability to resist high-calorie food, especially in obese individuals, according to a new study published in the Journal of Clinical Investigation. The findings suggest the area of the brain regulating impulsive behavior is less able to fight temptation for high-calorie food when blood glucose is low.

Researchers at USCs Keck School of Medicine of USC and Yale University studied lean and obese individuals whose blood sugar had been reduced intravenously with insulin. Using functional magnetic resonance imaging, they examined which areas of the brain were activated when the test subjects viewed pictures of different kinds of foods, from fatty foods like cake and ice cream to more healthy choices such as salads and fruit. The subjects rated their desire for the foods.

The found test subjects desire for higher-calorie foods happened when glucose levels dropped below normal. The brains of obese people in particular showed a lack of inhibition of impulsive desire for food.

The prefrontal cortex is the part of the brain that says stop eating, " the researchers said. When blood sugar levels are low, that area of the brain is less activated. Obese individuals lacked prefrontal brain activation even when sugar levels were normal. We dont know if obesity changes the way the brain responds or if it responds this way because of obesity."