Contributions of obesity, gender, hunger, food preference, and body size to bite size, bite speed, and rate of eating.

College students ate two high preference or two low preference doughnuts under high or low hunger conditions. Subjects were led to believe that we were interested in preference ratings made after eating the doughnuts. The number of bites and the total snack time were covertly recorded. Having weighed the doughnuts previously, we calculated the bite size (amount per bite), bite speed (time per bite), and eating rate (amount per second). Eating rate increased as obesity, body size, hunger, and preference increased; men ate at a faster rate than women. Larger bites accounted for the increased rate of the obese, the high preference subjects, and those having a larger body size. The hungry subjects increased their eating rate by taking faster bites. Men ate faster than women by taking both larger but slower bites. Thus eating rate is under multiple control. The data also suggest that the effects of obesity and, in part, gender on these eating responses may be more parsimoniously explained as body size effects. Modification of these within-session eating responses in order to regulate food intake will be successful only when the relationships among these measures are understood.