Teasing Out the Puzzle of Weight Suppression and BMI

Weight suppression, defined as the difference between highest past weight and current weight, has been used to predict increases in body mass index (BMI, kg/m²) during college and during eating disorders treatment. However, the mechanism or mechanisms underlying the predictive trends are not yet understood.

A team at the University of Oregon and the University of Wisconsin-Madison found that weight suppression could predict future increases in BMI but not bulimic symptoms (Am J Clin Nutr 2011; published ahead of print as doi:10.3945/ajcn.110.010025). Weight suppression among the 91 young women studied did show a moderate relationship to suppressed resting metabolic rate and total energy expenditure, but these variables do not appear to be involved with the predictive effect on future increases in BMI.

A study of twins

In a second study, Dr. Karen S. Mitchell and co-workers at Virginia Commonwealth University, Richmond, and the University of North Carolina-Chapel Hill, investigated associations between eating-disorder-related variables and weight suppression and additive genetic, common, and unique environmental contributions to weight suppression in a population-based sample of 1,503 female adult twins (Virginia Twin Registry).

Modeling results were similar for participants reporting no binge eating and those reporting binge eating with loss of control. Among those who did not binge eat, restraint, drive for thinness, body dissatisfaction, and dieting during childhood or adulthood were related to weight suppression. In the group that had binge eating and loss of control, restraint, disinhibition, and dieting during childhood were related to weight suppression.

Thus, the authors’ results suggest that weight suppression might be experienced differently or reflect different processes in persons with and without histories of binge eating. Dieting in childhood was most strongly associated with weight suppression within the subsample of women reporting binge eating.

The authors note that although the study results could not fully explain differences in healthy and unhealthy weight suppression, results of the current study do suggest that care must be taken when developing health promotion or obesity prevention programs that address the issue of weight suppression. Ideally, such programs or interventions could promote the idea of maintaining a healthy lower weight while not encouraging participants to strive for an unrealistically small body size that might trigger disordered eating in vulnerable persons.