Why are so many individuals with bulimia nervosa low in weight suppression?

BACKGROUND

Weight suppression (WS) is associated with many problematic characteristics in individuals with bulimia nervosa (BN). It is theorized that WS contributes to eating disorder (ED) characteristics through the initiation of metabolic and appetitive responses that contribute to dysregulated food intake and weight gain. However, some individuals with BN exhibit little or no WS, and we investigated two possible explanations for this: that low-WS individuals were once weight-suppressed but regained most of the weight they previously lost, or that low-WS individuals never underwent the large weight losses that some of those with BN have shown.

METHODS

Participants were 453 female patients with BN. We used mixed-model ANOVAs to compare individuals with low and high WS on four weight variables (i.e., premorbid high, postmorbid high, postmorbid low, and current z-BMI). We conducted these analyses using a new, developmentally sensitive measure called developmental weight suppression (DWS).

RESULTS

Our results revealed strikingly different weight histories between low and high WS groups. The high WS groups displayed dramatic weight losses (and only partial weight regain), but the low WS groups demonstrated only modest weight losses and an overall pattern of weight gain over time.

CONCLUSIONS

Individuals with BN and low WS do not show the same large and rapid z-BMI losses that are characteristic of most individuals with BN; rather, they show patterns of weight gain that are more characteristic of individuals with BED. Therefore, it may not be appropriate to include individuals who never lost significant weight in studies of WS in BN, as weight suppression would not be relevant to their presentation. Thus, there may be two groups of individuals with BN: those for whom weight suppression is a maintaining factor of binge eating, and those for whom it is not.