Abstract
Background: It has been suggested that highly palatable foods such as those containing fat and sugar and their access schedule could be an important factor to induce binge eating, a main symptoms of bulimia nervosa or binge eating disorder. In this study, using fat (vegetable shortening), we investigated effects of two types of feeding schedule (Intermittent access (IA) and Continuous access (CA)) and their combinations on eating behavior in rats. Method: Two groups of rats (Sprague-Dawley, male), which already habituated to fat, were subjected to IA (1h/day for 6 times) or CA (24h/day for the same periods as IA) to fat under free access to regular food. After 6 days of no fat access period (fat withdrawal period), 1h fat intake was measured and, subsequently, the each group of rats was subjected to alternate fat access schedule. After second fat withdrawal period, 1h fat intake was measured again. The 1h fat intakes after each schedule were compared. Results: The 1h fat intake during IA gradually increased relative to each basal 1h fat intake and binge-like overeating was established. The established overeating was still remained after the fat withdrawal period. On the other hand, daily 24h fat intake during CA did not increase and also 1h fat intake after the fat withdrawal period did not increase. In the case of group which had IA firstly, the IA-induced overeating was diminished by the experience of subsequent CA. In the case of group which had CA firstly, although 1h fat intake increased during IA period, the increased fat intake did not remain after the fat withdrawal period. In addition, fat intake experiences suppressed the intake of regular food during the fat withdrawal periods, especially after CA of the group which had IA first. Conclusion: Our results suggest that IA could be a factor to induce and maintain overeating of fat and CA could reverse and prevent the IA-induced overeating.
