The unique and interacting roles of internalized weight bias and fear of weight gain, and their associations with eating disorder symptoms

Both internalized weight bias (IWB), and fear of weight gain have been studied separately as contributors to eating disorder (ED) symptoms. IWB and fear of weight gain may be overlapping constructs as they both emphasize weight gain as an undesired and feared outcome. However, only fear of weight gain has been included in ED maintenance models. Additionally, no studies to date have investigated whether IWB and fear of weight gain act concurrently and independently of one another to impact ED symptoms, or whether they interact synergistically, causing compounding risk for ED symptoms. Therefore, the current study tested unique and moderating relationships among IWB, fear of weight gain, and ED symptoms in a higher ED risk population. This study was preregistered. Participants (N = 1233; 62.2 % women) completed one-time survey data. Eight ED symptoms were the main outcomes. Multiple linear regression models were conducted to assess main and interactive effects of IWB in the entire sample and in a subsample of individuals with probable EDs (n = 311). In the entire sample, there were no significant interactions, but in individuals with a probable ED, IWB moderated the relationship between fear of weight gain and cognitive restraint. There were also main effects of IWB on all ED symptoms, and main effects of fear of weight gain on seven symptoms. Results suggest that IWB may compound the impact of fear of weight gain on cognitive restraint among individuals with EDs. Both IWB and fear of weight gain had unique relationships with most or all outcomes, suggesting they are independent constructs. It is important that both IWB and fear of weight gain are targeted in ED treatment and IWB should be included in maintenance models of ED symptomatology.