Dieting by adult females is a common practice in Western society and nursing has long recommended dieting as a method of pursuing weight loss. The purpose of this study was to determine if psychological reactance according to Brehm's Theory of Psychological Reactance, occurred when normal eating behaviors were voluntarily eliminated. One of the major aims was to determine if psychological reactance occurred when the freedom of choice of eating was eliminated and whether there were any differences in the frequency of reactance between those on a restrictive and a non-restrictive 1200-calorie diet. The manifestations of reactance that were addressed were reestablishment of eliminated behavior, attacks on agent responsible for the threat, positive/negative valuation, and psychological pressure. Another aim was to examine the occurrence of manifestations of reactance within the context of restrained eating factors: cognitive restraint, disinhibition and hunger. Finally, the two diet groups were compared as to whether there were any differences in weight loss depending upon the restrictiveness of the diet.

Fifty-eight adult females volunteered to go on a diet for four weeks and record their experiences in a journal. The subjects were randomly assigned to one of two 1200-calorie diets varying in restrictiveness. On one diet the subjects could eat whatever they wanted within the 1200 calories; the other diet specified not only calories, but time of eating and type/amount of food. The journal data were analyzed by content analysis. Frequencies of categories were counted and analyzed statistically.

There were no differences in the frequency of occurrence of reactance manifestations between the restrictive and non-restrictive diets. Most of the dieters binged, most did not stay on the diet longer than seven days, and all experienced psychological reactance. There were no differences in the frequency of the reactance manifestations according to the restraint eating factors. However, the overweight group scored higher on the disinhibition factor than the non-overweight group. There was some weight loss over the four-week period, but there were no differences based on the type of diet.

The current health care practice of giving a standard, non-individualized diet with minimal instruction is not recommended. Based on this study, staying on a diet that restricts calories and eliminates freedom of choice is not feasible for adult females. When individuals do diet, they experience psychological pressure and physical side effects ranging from hunger and fatigue to weakness and dizziness. Counter-productive binge behavior is also common.