Exploring longitudinal relationships between fitness tracking and disordered eating outcomes in college-aged women

A growing body of research, primarily cross-sectional, suggests a relationship between the practice of tracking one's food intake and exercise behaviors using fitness-tracking smartphone applications ("apps") or wearable devices ("wearables") and disordered eating symptomatology. The aim of the present study was to explore longitudinal relationships between fitness tracking and disordered eating outcomes among college-aged women, as well as to determine whether the individual-level risk factors of pre-existing eating concerns, perfectionism, and rumination about food moderated the relationship.

N = 68 female undergraduates used the MyFitnessPal app for 8 weeks while completing a series of self-report measures.

At the trait level, fitness tracking frequency was positively associated with weight/shape concerns, but not with the other outcome measures. Daily levels of fitness tracking did not predict next-day levels for any of the outcome measures. Within-day fitness tracking at one timepoint was associated with lower reports of dietary restraint efforts at the next timepoint. None of the proposed moderators significantly interacted with the relationships over time.

These results suggest that while those who engage in fitness tracking may experience higher weight/shape concerns as a trait, over time fitness tracking was not associated with an increase in concerns. Further work exploring whether fitness tracking may affect particular subgroups in different ways is warranted.