Motivational interviewing to treat overweight/obesity: A meta-analysis of relevant research

Obesity in the U.S. has increased an alarming 37% between 1990 and 2006. Therefore, effective interventions need to be developed to decrease the rate of obesity. Motivational interviewing is one cognitive-behavioral strategy that could be used to treat obesity, however to date the current evidence of its effectiveness is mixed. The purpose of this study is to meta-analytically examine the effectiveness of motivational interviewing in treating obesity and the difference in magnitude of effect as it pertains to gender, socioeconomic status, ethnicity and practitioner conducting the intervention. There were 41 trials that analyzed the effectiveness of motivational interviewing in changing diet, physical activity, and body weight included in this meta-analysis. In terms of overall effectiveness, there was a moderate effect of motivational interviewing on all outcomes (d. = 0.29) with a success rate of 57%. Motivational interviewing was most effective in changing dietary behavior (d. = 0.35). There were significant moderator effects of gender, socioeconomic status, ethnicity and practitioner on dietary intake outcomes but not physical activity or weight outcomes, indicating that motivational interviewing is more effective for females, middle/mixed socioeconomic status, Caucasians and trained practitioners. From the results of this study, it can be concluded that motivational interviewing has the potential to be an effective treatment for obesity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)