At the start of weight loss, rats randomized to the EX groups were acclimated to treadmill exercise (Exer-6M Treadmill; Columbus Instruments). The first 4 weeks were a ramp up phase where time and speed were gradually increased to the final prescribed dose of exercise, which was 15 m/min for 60 min/day, 6 days/week. Exercise bouts occurred during the light cycle within 2 hours of the start of the dark cycle. Rats reached the full speed and time while they were in the weight maintenance phase and remained at the same full speed and time until euthanasia. Our pilot data indicated that the energy expended during treadmill exercise was very similar (<0.5 kcal difference) between OP and OR rats (data not shown). Rats were scored from 1 (worst) to 10 (best) during each bout of exercise based on the quality of running and amount of encouragement required to complete the exercise bout, as previously described (19 (link)).