Central Role of Cognitive Control Networks in Weight Loss During Voluntary Calorie Restriction
Insufficient responses to hypocaloric diets have been attributed to hormonal adaptations that override self-control of food intake. We tested this hypothesis by measuring brain fMRI reactivity to food cues and circulating energy-balance hormones in 24 overweight/obese participants before, and 1 and 3 months after starting a calorie restriction diet. Increased activity in prefrontal regions at month 1 correlated with weight loss at months 1 and 3. Weight loss was also correlated with increased plasma ghrelin and decreased leptin at month 1, and these changes were associated with greater food cue reactivity in reward-related brain regions. However, the reduction in leptin did not counteract weight loss; indeed, it was correlated with further weight loss at month 3. Activation in a network of prefrontal regions associated with self-control could contribute to individual differences in weight loss and maintenance, whereas we failed to find that the hormonal adaptations play a major role.