How Carbs Can Trigger Food Cravings

Are all calories created equal? A new study suggests that in at least one important way, they may not be.

Sugary foods and drinks, white bread and other processed carbohydrates that are known to cause abrupt spikes and falls in blood sugar appear to stimulate parts of the brain involved in hunger, craving and reward, the new research shows. The findings, published in The American Journal of Clinical Nutrition, suggest that these so-called high-glycemic foods influence the brain in a way that might drive some people to overeat.

(..)

Regardless of the diet they choose, most people who lose a great deal of weight have a difficult time keeping it off for good. For many people, despite their best efforts, the weight returns within six months to a year. But a few studies of weight loss maintenance, including a large one in The New England Journal of Medicine in 2010, have reported some success with diets that limit high-glycemic foods like bagels, white rice, juice and soda.

In addition to raising blood sugar, foods that are sugary and highly caloric elicit pronounced responses in distinct areas of the brain involved in reward. Earlier imaging studies have shown, for example, that the main reward and pleasure center, the nucleus accumbens, lights up more intensely for a slice of chocolate cake than for blander foods like vegetables, and the activation tends to be greater in the brains of obese people than it is in those who are lean.