There are simultaneous epidemics of dieting, overweight and bulimia in the developed world. These symptoms are also closely correlated in most epidemiologic studies. That is, the more overweight you are, the more you diet and the more you binge eat. Which comes first?
A prevalent hypothesis is based on the presumption that frequent consumption of large quantities of food leads to weight gain and so the overeating comes first.
A better theory is that the dieting comes first.
In epidemiologic studies, like one in the January edition of Pediatrics, the symptoms of poor satisfaction with body shape is more tightly correlated with bulimia than weight for height. In this study a group of investigators from the University of Minnesota looked at a school-based sample of 4746 boys and girls in public middle and high schools. To asses the eating behaviors of these 11 to 18 year olds, they asked questions like: "In the past year, have you ever eaten so much food in a short period of time that you would be embarrassed if others saw you?" and "During the times when you ate this way, did you feel you couldn't stop eating or control what or how much you were eating?" and "How often did you eat large amounts of food, plus feel like your eating was out of control?" These symptoms of bulimia are the same symptoms shown by people who are starving. And, as we mentioned above, they are more tightly correlated with dieting that with being overweight in most studies. In this study, the connection between dieting and poor self image and the bulimia symptoms remained after correcting for weight and the connection between any of those and overweight was not statistically significant in the girls. It was in the boys.
Way back in 1985, we distributed a questionnaire in Lincoln Tower, a women's dorm at Ohio State University. We asked, "What do you weigh now?" and "What is the most you've ever weighed?" and questions about the symptoms of bulimia including "How often have you induced yourself to vomit?" Wefound a very tight connection between weight loss and the symptoms of bulimia. In fact very few women, 86 out of 759 completed questionnaires, 18, 19, and 20 year olds, weighed the most they had ever weighed at the time of the study. That is 90% of them were at some degree of reduced weight. They were all dieting. And the more reduced they were the more likely they had bulimia.
I think that the sequence of events is thus: poor self regard, especially if you are overweight, then dieting and then binge eating. Of course that completes the vicious cycle to even worse self esteem.