An imaging study reveals how the brains of some dieters stay disciplined and others give in to cravings. Researchers at the California Institute of Technology asked volunteers trying to slim down to pick a food toward which they felt neutral in terms of health and taste (many chose yogurt). They next scanned the dieters’ brains as they chose between this reference item and either healthy snacks, such as apples, or junk foods, such as candy bars. The team linked a brain region, the ventromedial prefrontal cortex, with the desire for tasty items, regardless of how unhealthy they might be. A separate area, the dorsolateral prefrontal cortex, was associated with self-control; dieters who had strong signals in this region chose the healthier food even if they did not think it tasted better. The findings, in the May 1 Science, present new targets that could help treat not only obesity but also addiction, wasteful spending, and other matters dealing with desire and restraint.