A mixed-methods longitudinal examination of weight-related self-monitoring and disordered eating among a population-based sample of emerging adults.

Abstract

Background: Weight-related self-monitoring (WRSM) apps are used by millions, but the effects of their use remain unclear. This study examined longitudinal relationships between WRSM and disordered eating among a population-based sample of emerging adults.

Methods: Participants (n = 138) were recruited from EAT 2010-2018 (Eating and Activity over Time study) to participate in a mixed-methods (quantitative and qualitative) longitudinal study to understand the impacts of WRSM. In 2018, participants (M_age=21.7 ± 1.9 years) reported motivations for use and types of WRSM apps used. Dependent variables collected in 2022 (M_age=25.7 ± 1.9 years) included past year total number of disordered weight control behaviors, disordered muscle building behaviors, compulsive exercise, and binge eating. Linear and logistic regressions were used adjusting for sociodemographics, body mass index, and baseline disordered eating. Semi-structured interviews (n = 25) were analyzed using inductive thematic analysis.

Results: Participants using WRSM apps for weight management demonstrated an increase in disordered weight control behaviors over time (β = 0.894, p = .012). Using WRSM apps for "healthy" eating was marginally associated with an increase in disordered weight control behaviors. (β = 0.673, p = .052). Qualitatively, participants reported varied temporality between WRSM and disordered eating, but believed that app use encouraged restriction/binge cycles and normalized disordered eating.

Conclusions: Findings suggest there may be individual variation in the relationships between WRSM and disordered eating, but that using WRSM apps with the motivation of managing eating or weight may increase disordered eating in some. Additionally, WRSM apps may normalize or encourage disordered eating. Therefore, safeguards, including screening and monitoring, are needed to ensure WRSM does not cause or escalate harm among WRSM users.