JMIR Publications

ABSTRACT

Background:

Online pro-eating disorder (pro-ED) communities are considered harmful due to their detrimental effects on their users’ body dissatisfaction, dieting, and help-seeking. So far, it is unknown to which extent participation in pro-ED communities affects users’ body weight and desired weight loss.

Objective:

We investigated changes in current and desired bodyweight of users of a pro-ED community (r/proed) on the social media website Reddit over time.

Methods:

Methods:

Data on N = 1,170 users and the unsolicited weight information they shared with the pro-ED community were collected over a period of 15 months. Linear growth models were used to model change in users’ current and desired Body Mass Index (BMI) over time.

Results:

Both current and desired BMI decreased over time with a predicted rate of 0.087 and 0.015 BMI points per week respectively. Weight loss was moderated by the users’ activity level in the community with more active users losing more weight. Users at higher baseline BMI experienced greater weight loss but even users at a very low baseline weight (BMI < 17) lost weight during their participation. In addition, users decreased their desired weight over time with many pursuing extremely low, unrealistic weight goals. Changes in desired weight were moderated by baseline current BMI and baseline desired BMI. Users with higher desired weight and lower bodyweight at baseline decreased their desired weight more over time.

Conclusions:

This is the first study that could demonstrate the detrimental effects of pro-ED communities in a longitudinal study based on a large dataset of user generated online data. The results extend the literature detailing harmful effects of online pro-ED communities by showing users’ weight loss, decreases in desired weight, and that higher activity levels lead to greater weight loss. Users could be driven to pursue very low, unrealistic weight loss goals by the thin ideal presented in these communities.