A structured intentions and action-planning intervention improves weight loss outcomes in a group weight loss program

Am J Health Promot. Nov-Dec 2013;28(2):119-27. doi: 10.4278/ajhp.120727-QUAN-365. Epub 2013 Apr 26.

Abstract

Purpose: To assess whether forming general behavioral intentions and implementing intentions through action plans promotes weight loss and is moderated by weight loss goals and self-efficacy.

Design: A quasi-experimental study comparing change in body mass index (BMI) for 15 months between a behavioral intentions condition (BIC), an implementation intentions condition (IIC), and a comparison condition (CC).

Setting: Ten-week weight loss program delivered in weekly group meetings at community medical centers.

Subjects: Six hundred thirty-two attendants at the weight loss program (80% of program attendants participated in the study).

Intervention: Weight loss program focused on lifestyle changes, augmented by two experimental conditions (vs. a comparison condition): BIC, intended use of weight loss techniques; IIC, intended use and detailed plans for two techniques. Phone follow-up was conducted 3 and 12 months later.

Main outcome: BMI during the program (computed on the basis of weight and height measured on a mechanical medical scale). Experimental manipulations included exposure to list of techniques (BIC/IIC) and structured planning form (IIC); independent variables were assessed with questionnaires (eating self-efficacy, weight loss goal, demographics).

Analysis: Linear mixed models estimating changes in BMI and their interactions with the planning interventions, goals, and self-efficacy.

Results: Participants in the BIC and IIC lost 40% more weight during the 10-week program than those in the CC (1.10 and 1.11 BMI points compared with .79; ts < -2.76, ps < .01). Weight loss goals interacted with implementation intentions (t = 2.98, p < .01). Self-efficacy was unrelated to weight loss. No differences were found between conditions at 3 and 12 months after the program.

Conclusion: Findings revealed that forming implementation intentions promotes weight loss within a weekly program at a field setting and that its effectiveness depends on initial high goals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Body Mass Index
  • Community Health Centers
  • Goals
  • Health Promotion / organization & administration*
  • Humans
  • Israel
  • Life Style
  • Middle Aged
  • Outcome and Process Assessment, Health Care*
  • Self Efficacy
  • Surveys and Questionnaires
  • Weight Loss*