In a study that offers hope for human dieters, rats on a 30-day diet who exercised intensely resisted cues for favored, high-fat food pellets. The experiment was designed to test resistance to the phenomenon known as 'incubation of craving,' meaning the longer a desired substance is denied, the harder it is to ignore signals for it. The findings suggest that exercise modulated how hard the rats were willing to work for cues associated with the pellets, reflecting how much they craved them.