The sight of food turns different parts of the brain on in lean versus obese people, a new study finds
In obese people, even when the brain knows the body isn’t hungry, it responds to food as if it were, new brain-scan data show. That means that when obese people try to shed weight, they may find themselves on the losing side of a battle with neural centers that unconsciously encourage them to eat.
For instance, in normal-weight people a neural reward system that reinforces positive feelings associated with food turns off when levels of the blood sugar glucose return to normal after a meal — a signal that the body’s need for calories has been sated. But in obese people, that reward center in the central brain turns on at the sight of high-calorie food even when their blood sugar levels are normal.
The new findings show that “the regulatory role of glucose was missing in the obese,” says Elissa Epel of the University of California, San Francisco, an obesity researcher not involved with the new study. She says the data might “explai