Do impulse control difficulties moderate the relationship between intermittent fasting and disordered eating?

Background: Recent findings suggest positive associations between intermittent fasting (IF, i.e., an eating pattern that consists of alternating between consuming and abstaining calories over specified periods of time) and disordered eating (DE), including binge eating, laxative use, and self-induced vomiting. However, as not all individuals who engage in IF present with DE, the current study aimed to investigate whether 1) IF was associated with elevated DE, and 2) impulse control difficulties differentially predict DE in intermittent fasters compared to non-intermittent fasters.

Methods: Participants included 929 undergraduates (M = 19.8, SD = 2.97) from a university in the United States. IF was assessed with a single item question, "Do you intentionally engage in intermittent fasting in order to lose/maintain your weight or due to health-related motivations?" The Eating Disorder Examination Questionnaire was used to measure DE (i.e., global score, restraint, eating, shape, and weight concerns). One subscale from the Difficulties in Emotional Regulation Scale was used to measure impulse control difficulties. Hierarchal regressions examined whether impulse control difficulties moderated the relationship between IF and DE while controlling for age, gender, race, and ethnicity.

Results: IF was significantly associated with all DE outcomes. Adjusted analyses indicated that impulse control difficulties moderated the relationship between IF and two DE outcomes (i.e., global score (b = 0.038, se = 0.017, t = 2.17, p < 0.05) and restraint (b = 0.042, se = 0.019, t = 2.22, p < 0.05)).

Discussion: These results support previous literature that suggests an association between IF and elevated DE. Further, individuals engaging in IF with impulse control difficulties may experience more feelings of restraint towards eating and increased overall DE though effects were small. Future research delineating who is at highest risk for DE when engaging in IF is needed.