Motivation to change predicts naturalistic changes in binge eating and purging, but not fasting or driven exercise among individuals with eating disorders.

We examined the naturalistic relations between motivation to change and change in four specific eating disorder (ED) behaviors-binge eating (BE), purging, fasting, and driven exercise-in a community-based sample of individuals with EDs over two consecutive 6-week periods. We conducted cross-lagged generalized estimating equations using the transtheoretical model's four stages of change to predict changes in the ED behaviors 6 weeks later. Individuals reported lower pre-contemplation for behaviors typically associated with more distress (e.g., BE, purging) than they did for behaviors associated with less distress (e.g., fasting and driven exercise). Action predicted decreases in BE and purging frequencies but not fasting or driven exercise frequencies. Naturalistic relations between ED behavior severity/frequency and motivation to change these features can be detected over 6-week intervals; that is, attempts at change in individuals' natural environments can be successful over relatively brief periods of time, especially when individuals experience the motivation to change these features. The process of motivation to change ED behaviors is not linear, and our study highlights the movement between stages of change among individuals with EDs. Future research is needed to examine how much of the observed changes are sustained.