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

## TL;DR

The study finds that some individuals with bulimia nervosa have low weight suppression due to different weight histories compared to those with high weight suppression.

## Contribution

The study introduces a developmentally sensitive measure of weight suppression and identifies distinct weight history patterns in bulimia nervosa subgroups.

## Key findings

- Low weight suppression in bulimia nervosa is linked to modest weight losses and overall weight gain over time.
- High weight suppression is associated with dramatic weight losses and partial weight regain.
- The weight suppression model may not apply to individuals with bulimia nervosa who never experienced significant weight loss.

## Abstract

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.

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).

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.

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.

The online version contains supplementary material available at 10.1186/s40337-025-01301-2.

Weight suppression (WS), the difference between one’s highest past weight (or, for those with diagnosed eating disorders, their highest premorbid past weight) and current weight, has been found to be associated with symptom severity and treatment outcome among individuals with bulimia nervosa. It is theorized that these associations are due to metabolic and appetitive responses to being in a weight-suppressed state, yet some individuals with bulimia nervosa exhibit very low or no WS. This may be because they were once highly weight suppressed and have subsequently gained weight, or it could be that this subgroup was never significantly weight suppressed. We compared the weight histories of individuals with bulimia nervosa with low or no WS with individuals with bulimia nervosa with high WS. We found that the low WS subgroup has a dramatically different weight history than those high in WS, displaying only modest weight losses and a general pattern of weight gain over time. This suggests that the weight suppression model may not be applicable for this subgroup.

The online version contains supplementary material available at 10.1186/s40337-025-01301-2.