Motivation and its relationship to adherence to self-monitoring and weight loss in a 16-week Internet behavioral weight loss intervention.

OBJECTIVE

To examine changes in motivation and the relationship of motivation to adherence to self-monitoring and weight loss in a 16-week Internet behavioral weight-loss intervention.

DESIGN

Two-group randomized design.

SETTING

This study was conducted over the Internet.

PARTICIPANTS

Sixty-six women, ages 22-65, with a body mass index (BMI) between 25 and 40, and with a home computer with Internet access, participated.

INTERVENTION

These data are from an Internet behavioral weight-loss program in which all participants received a face-to-face initial session followed by the 16-week Internet program.

MAIN OUTCOME MEASURES

Adherence to self-monitoring and weight loss were the main outcome measures.

ANALYSIS

Linear regression and mediation analysis using the Baron and Kenny method were conducted.

RESULTS

Autonomous motivation increased initially and remained high for those who ultimately achieved a 5% weight loss, but declined over time for participants who did not achieve a 5% weight loss. Autonomous motivation at 4 weeks was a predictor of adherence to self-monitoring and 16-week weight loss. Adherence mediated the relationship between autonomous motivation and weight loss.

CONCLUSIONS AND IMPLICATIONS

These results suggest that autonomous motivation may be a promising intervention target for promoting program procedure adherence and weight loss.