Elevated pre‐morbid weights in bulimic individuals are usually surpassed post‐morbidly: Implications for perpetuation of the disorder

In Russell’s initial characterization of bulimia nervosa (BN), he suggested that while the body weights of patients with this eating disorder are typically “unremarkable” when they present for treatment, they are usually significantly below their highest pre-morbid weights (1). Indeed, those with BN have usually lost so much weight in the past that about one-third to one-half have a history of anorexia nervosa (2). Aside from this distinction, most researchers and clinicians have paid little attention to the fact that at presentation most BN individuals are further below their highest previous body weights than are non-eating disordered individuals of the same age (3). This may be because these patients’ weights are usually neither low enough to create the physiological or psychological consequences associated with an abnormally low body weight nor high enough to elicit concerns about the possible medical and psychological consequences of overweight. Similarly, in the effort to explain why only a small fraction of young women concerned about their bodies develop problems related to BN (4), potential weight-related predispositions have been overlooked relative to psychological predispositions (e.g., low self-esteem, poor body image, etc.). However, it is possible that a susceptibility toward excessive weight gain puts certain young women at greater risk for developing BN. Evidence suggests that women who develop BN have higher relative weights pre-morbidly than their same aged peers and are more likely to have one or both parents who are obese (5). Studies examining appetitive indicators in patients with bulimia have also shown an exaggerated appetitive response to food stimuli relative to healthy controls (i.e. 6, 7,8). The fact that individuals with BN are often in the normal weight range but have a history of overweight indicates that at presentation they weigh considerably less than their highest weight (9,10). Lowe (11) called the discrepancy between one’s highest ever and current weight “weight suppression” and research indicates that those with BN have elevated weight suppression relative to their non-bulimic peers (3). Recent research has shown that weight suppression level in those with BN predicts frequency of binge eating and purging (3,12), amount of weight gain over a period of several months (13,14) and over 5 years (15), and poorer outcome in CBT (3). Furthermore, recent research (16) found that weight suppression level predicted the probability of developing a BN-spectrum disorder over 10 years among young women initially without this disorder. Our research on weight suppression has always assumed that the historical highest weights of those with BN were reached before their eating disorder began (e.g. 13). Bulimic patients typically lose a significant amount of weight in the process of developing their disorder (9,10) and then engage in extreme weight control behaviors to avoid weight gain. Nonetheless, as we began to ask individuals with BN about their weight history, we were surprised to learn that some individuals reported reaching their highest weight after their disorder developed. Because there is evidence that the pre-morbid body weights of those with BN are already elevated (9), such evidence would suggest that BN individuals are even more prone toward weight gain than current models of BN generally assume. In this regard it is interesting to note that the eating disorder of BN was first identified (1)at about the same time the prevalence of obesity in the United States started accelerating (around 1980; 17). Determining the percent of individuals with BN who reached their highest past weight pre-versus post-morbidly is important for several reasons. First, because those with BN already have higher relative weights than their same-age peers before developing their disorder (5), if some reach even higher weights following onset it would strengthen the possibility that individuals with BN have a predisposition toward overweight or obesity. Second, since most of those with BN reach very low body weights during their disorder, such a finding would indicate that the degree of weight fluctuation experienced by those with BN is even larger than previously suspected. Third, if during their disorder some patients with BN reach a higher weight than their highest pre-morbid weight, it would suggest that bulimic behavior patterns (i.e., restricting, bingeing, purging) might contribute to post-morbid weight gains. Fourth, the notion that individual BN patients have the potential to not only lose but to gain a great deal of weight could suggest a reinterpretation of a core feature of BN which has variously been referred to as a “morbid fear of fatness,” and a“ persistent over-concern with body shape and weight,” (see 18). If many patients with BN have a history of being overweight at some point during (not just prior to) the development of their disorder, then patients’ persistent fears of weight gain might be viewed in part as a realistic concern based on their own weight history. Finally, and perhaps most significantly, if the weight fluctuations experienced by individuals with BN are larger than previously suspected, this information may be important in shaping the goals of treatment. In particular, a patient’s body weight, both in absolute terms and in relation to their highest previous body weight, could influence the interpretation of a patient’s weight and shape concerns and also suggest that weight changes during and after treatment should become an explicit topic of discussion in therapy. The purpose of this paper was therefore to determine what percentage of individuals with BN report their highest weight after as opposed to before the onset of their disorder, as well as to determine how much weight those who supersede their previous highest weight gain during their disorder. Additionally, we attempted to confirm whether previous evidence indicating elevated pre-morbid weights relative to same-aged peers (5) could be replicated in our samples. Finally we compared sub-groups of individuals with BN who reported reaching their highest previous weight before or after onset of their disorder on various measures of eating disorder psychopathology to determine if the timing of reaching one’s highest weight is related to severity of eating disorder symptoms. We analyzed two data sets to explore these questions. One was derived from a treatment study conducted among patients with BN enrolled in an intensive outpatient program. The other was derived from a longitudinal study of BN that has followed a group of individuals with that disorder over a 10-year period (19). This latter data set allowed us to explore these questions not only retrospectively (i.e., looking backward from the time participants enrolled in the study) but also prospectively to determine what percentage of individuals with BN subsequently gained enough weight to supersede their pre-enrollment highest body weight.