Eating regulation: The role of restraint, dieting, and weight

The present study evaluated two assumptions of restraint theory. The first is that “restrained eating” and “dieting” are functionally equivalent. The second is that the effect of dieting on eating regulation is similar in normal-weight and overweight individuals. The first hypothesis was tested by examining, using the standard forced preload paradigm, the eating of normal-weight women classified as unrestrained nondieters, restrained nondieters, and restrained dieters. A significant restraint/dieting x preload interaction emerged. Restrained dieters ate much more without a preload than with one, while the two nondieting groups showed the opposite tendency. The second assumption was tested by reclassifying these normal weight subjects simply as dieters or nondieters and running additional groups of dieting and nondieting overweight subjects through the preload manipulation (creating a Weight x Dieting x Preload factorial). A three-way interaction was found. Among normal-weight subjects, nonpreloaded dieters overate; among overweight subjects, nondieters overate. Implications of these findings for restraint theory and the boundary model of eating were discussed.