Meal pattern during the transient hypophagia of rats switched from a high fat to a high carbohydrate diet

Meal pattern was investigated during the transient hypophagia lasting about 1 week when rats are switched from a carbohydrate-free high fat (HF) diet to an isocaloric high carbohydrate (HC) diet. After the HF/HC diet switch, voluntary food intake was suppressed through reduction of meal size with meal frequency remaining unaffected. Thus, the satiety ratio was increased in HF rats ingesting the HC diet. The observation that the first meal after the HF/HC switch, unlike the following meals, was not yet diminished, suggests that conditioning is involved in the reduction of meal size resulting from the switch. About 1 week after the dietary switch, the feeding pattern of rats had adjusted to that of rats receiving the HF diet. Unlike the HF/HC switch, the HC/HF switch did not reduce cumulative food intake, but decreased meal size and increased meal frequency during the first day. It is suggested that the transient decrease in meal size and increase in satiety ratio following the HF/HC diet switch arises partly from a relatively high postabsorptive satiating potency of glucose related to a low rate of glucose disposal found in previous work under such conditions. A transiently reduced gastrointestinal clearance of carbohydrate may also be involved.