A naturalistic examination of feeling fat: Characteristics, predictors, and the relationship with eating disorder behaviors.

Objective: Although literature implicates feeling fat in the maintenance of binge-spectrum eating disorders (EDs; e.g., bulimia nervosa, binge-ED), research in this area is small, nascent, and relies on retrospective self-report. The current study sought to understand the temporal pattern of feeling fat and its role as a precipitant and consequence of ED behaviors.

Methods: Totally 106 treatment-seeking adults with binge-spectrum EDs completed 7-14-day ecological momentary assessments. They rated feeling fat, negative affect states, and reported on ED behaviors six times per day. Multilevel models evaluated whether feeling fat mediates prospective links between negative affect states and ED behaviors, assessed if negative affect states mediate the prospective association of feeling fat on ED behaviors, and examined the bidirectional prospective association between feeling fat and ED behaviors.

Results: Feeling fat was highest in the early morning (6-8:59 a.m.). Individuals with binge-ED-spectrum EDs demonstrated greater variability in feeling fat than those with bulimia nervosa-spectrum EDs who had stable and high levels of feeling fat. Guilt, sadness, anxiety, and the overall NA at Time 2 mediated the prospective associations between at Time 1 feeling fat and Time 3 dietary restraint, actual dietary restriction, and compensatory exercise. There was a bidirectional prospective association between feeling fat and binge eating.

Discussion: Feeling fat serves as a proximal predictor and mediator of the prospective association between guilt and binge eating. Feeling fat and binge eating mutually reinforce each other.

Public Significance: Little is understood regarding the experience of feeling fat in natural environments among individuals with binge-spectrum eating disorders. We found that the risk for having the experience of feeling fat is high in the morning and evening. Feeling fat triggers guilt, anxiety, and sadness which in turn, increases engagement in dietary restraint/restriction and compensatory exercise. Feeling fat also triggers binge eating, and binge eating leads to feelings of fatness.