Sham feeding in the rhesus monkey.

Adult male rhesus monkeys with chronic gastric fistulas were adapted to eating a liquid food during a 90 min test period after an overnight food deprivation. When the fistulas were opened for the first time, monkeys sham fed more than three times as much as they had eaten the previous day when the gastric fistulas were closed. The observed incidences of resting and non-ingestive activity were reduced during the sham feeding test. When monkeys sham fed for 5 successive test days, intake increased progressively with a concomitant decrease in the incidence of non-ingestive activity. The results demonstrate that under, these experimental conditions pregastric food stimuli (and their conditioned and/or unconditioned responses) are not sufficient to limit meal size at control levels, and they are not sufficient to elicit the behavioral sequence of normal satiety.