Social support for healthy behaviors: Scale psychometrics and prediction of weight loss among women in a behavioral program

Abstract

Social support could be a powerful weight-loss treatment moderator or mediator but is rarely assessed. We assessed the psychometric properties, initial levels, and predictive validity of a measure of perceived social support and sabotage from friends and family for healthy eating and physical activity (eight subscales). Overweight/obese women randomized to one of two 6-month, group-based behavioral weight-loss programs (N = 267; mean BMI 32.1±3.5; 66.3% White) completed subscales at baseline, and weight loss was assessed at 6 months. Internal consistency, discriminant validity, and content validity were excellent for support subscales and adequate for sabotage subscales; qualitative responses revealed novel deliberate instances not reflected in current sabotage items. Most women (>75%) never or rarely experienced support from friends or family. Using nonparametric classification methods, we identified two subscalessupport from friends for healthy eating and support from family for physical activitythat predicted three clinically meaningful subgroups who ranged in likelihood of losing 5% of initial weight at 6 months. Women who never experienced family support were least likely to lose weight (45.7% lost weight) whereas women who experienced both frequent friend and family support were more likely to lose weight (71.6% lost weight). Paradoxically, women who never experienced friend support were most likely to lose weight (80.0% lost weight), perhaps because the group-based programs provided support lacking from friendships. Psychometrics for support subscales were excellent; initial support was rare; and the differential roles of friend vs. family support could inform future targeted weight-loss interventions to subgroups at risk. © 2011 The Obesity Society.