Detrimental effects of irregular meals on rats' ability to adjust to meal feeding.

Male rats were fed for two hr a day at the same time each day (regular meals) or for two hr a day at one of three different times (irregular meals) but with an average intermeal interval of 22 hr. Regularly fed rats were able to learn to eat enough to grow at the same rate as control animals which had ad lib access to food. Irregularly fed rats (a) ate significantly less than regularly fed rats, even when the former were more food-deprived at the time of feeding than the latter, and (b) were unable to learn to eat enough to grow at the same rate as control animals. Irregular meals appear to retard a conditioning process in which cues associated wih feeding acquire the ability to increase food consumption.