The use of motivational interviewing techniques to enhance the efficacy of guided self-help behavioral weight loss treatment

This study assessed whether motivational interviewing (MI), applied as part of a standard guided self-help (GSH) behavioral weight loss treatment, reduced attrition rate and improved participant weight loss and other eating-related and general psychological measures. The study also included assessments based on two theories of motivated behavior, to assess whether these measures predicted treatment outcome and whether MI increased participant motivation. Thirty-nine overweight patients (7 males, 32 females) were randomized to receive either 6 sessions of traditional GSH and 2 traditional motivation-focused sessions (GSH); or 6 GSH sessions and 2 sessions utilizing an MI approach to motivation (MI/GSH). In intention-to-treat and completer analyses, significant differences were found in the areas of eating concern and control over eating, favoring MI/GSH. Between-group effect size estimates indicated a small to medium advantage for MI/GSH over GSH in weight loss, as well as on a number of secondary eating-related measures. Analyses of motivational measures indicated no significant differences by treatment group, but suggested that individuals who were more confident in their abilities to change and endorsed more extrinsic reasons for change lost more weight than other participants. Implications and future directions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)