How prescriptive support affects weight loss in weight-loss intervention participants and their untreated spouses.

Objective: Controlling or prescriptive support styles (e.g., pressure) often hinder weight loss, but can sometimes be beneficial. This secondary analysis of data from a randomized controlled trial examined persuasion, pressure, and indirect social control among cohabiting couples and the effect of these supports on weight loss.

Methods: Couples ( = 130) were randomized to either Weight Watchers (WW) or a self-guided control condition (SG). Only one member of each couple received the intervention; the other member of the couple was untreated. Couples were weighed and completed study measures at baseline, 3, and 6 months.

Results: Dyadic multilevel models examined BMI change and differences across role (treated participant/untreated spouse) and condition (WW/SG). Prescriptive support predicted BMI change for treated participants in the WW condition only. For treated WW participants, there was no significant decrease in BMI when pressure was high (+1), = -.25, = .22, but a significant decrease when pressure was low (0), = -.96, < .001. Additionally, high levels of indirect social control (+1) predicted greater decreases in BMI compared to low (-1) indirect social control, = -.91, < .001, and, = -.41, < .01.

Conclusions: Considering both the type and context of support for weight management is worthwhile. Intervention participants had access to treatment resources that may have engendered more effective responses to spouses' concerns or a sense of obligation to their spouse (indirect social control), whereas pressures to lose weight-while engaged in treatment-may have undermined behavior-change efforts. (PsycINFO Database Record