Voluntary exercise contributed to an amelioration of abnormal feeding behavior, locomotor activity and ghrelin production concomitantly with a weight reduction in high fat diet-induced obese rats

•Disrupted rhythms of feeding and locomotor activity were demonstrated in HFD-fed obese rats.•Voluntary exercise brought about an effective reduction of weight and fat in this obese model.•The disrupted rhythms of feeding and activity were ameliorated by voluntary exercise.•A deteriorated ghrelin production in this obese model was restored by voluntary exercise.•It is feasible that the daily rhythm amendment is related to a restoration of ghrelin production.