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Open Access Highly Accessed Study protocol

Increasing the effectiveness of the Diabetes Prevention Program through if-then plans: study protocol for the randomized controlled trial of the McGill CHIP Healthy Weight Program

Bärbel Knäuper1*, Elena Ivanova1, Zhen Xu1, Melodie Chamandy1, Ilka Lowensteyn2, Lawrence Joseph3, Aleksandra Luszczynska45 and Steven Grover2

Author Affiliations

1 Department of Psychology, McGill University, 1205 Dr. Penfield Avenue, Montreal H3A 1B1, QC, Canada

2 Comprehensive Health Improvement Program, McGill University, 5400 Westbury Avenue, Montreal H3W 2W8, QC, Canada

3 Department of Epidemiology and Biostatistics, McGill University, 687 Pine Avenue West, V Building, Montreal H3A 1A1, QC, Canada

4 Department of Psychology, Trauma, Health, and Hazards Center of the University of Colorado, 1420 Austin Bluffs Parkway, University Office Center, Colorado Springs, CO 80933-7150, USA

5 Department of Psychology, University of Social Sciences and Humanities, 30 Ostrowskiego St, 53238 Wroclaw, Poland

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BMC Public Health 2014, 14:470  doi:10.1186/1471-2458-14-470

Published: 18 May 2014



The Diabetes Prevention Program (DPP) is highly effective in promoting weight loss in overweight and obese individuals. However, one-on-one DPP sessions are costly. As a cost-saving alternative, a group version of the DPP, called Group Lifestyle Balance program (GLB), has been developed but has been shown to be less effective. The aim of this two-arm parallel randomized controlled trial is to increase the effectiveness of the GLB by integrating habit formation techniques, namely if-then plans and their mental practice, into the program.


A total of 154 participants will be randomized to a standard or enriched GLB program. For the enriched GLB program, if-then plans and their mental practice will be integrated into the standard GLB program. Participants will be overweight or obese men and women (BMI of 28 to 45 kg/m2, waist circumference ≥ 88 for women, ≥ 102 for men, 18 to 75 years of age) who do less than 200 minutes of self-reported moderate or vigorous exercise per week. Measures will be completed at baseline, 3 months, post-intervention (12 months), and 12 months post-intervention (24 months). The primary outcome measure is weight loss at 3, 12, and 24 months. Secondary outcomes include percent reaching weight loss goal, physical activity at 3, 12, and 24 months, and weight-related risk factors (waist circumference, hemoglobin A1c, systolic/diastolic blood pressure, total cholesterol/HDL ratio). Standardized training of the life-style coaches, use of standardized manuals, and audio taping and reviewing of the sessions will ensure intervention fidelity.


The study will provide evidence-based data on the effectiveness of an enhanced GLB intervention in promoting weight loss and in reducing weight-related risk factors for chronic health problems. Ethical clearance has been received from the Research Ethics and Compliance Board of the Faculty of Medicine Research and Graduate Studies Office at McGill University (Montreal, Canada).

Trial registration Identifier: NCT02008435. Registered 6 December 2013.

Lifestyle modification program; Implementation intentions; Mental imagery; Mental practice; Eating behavior; Physical activity; Weight-loss; Chronic disease; Habit formation