Greater intrinsic motivation for engaging in healthy lifestyle behaviors is associated with reduced postpartum weight

Abstract

Objective: Lifestyle behaviors impact postpartum weight, yet intrinsic motivation for them—i.e., what individuals enjoy, value, and do with ease—is poorly understood. The Pregnancy, Lifestyle and Environment Study-2 (PETALS-2) examined whether intrinsic motivations for engaging in healthy eating, physical activity, and weight self-monitoring are each associated with long-term postpartum weight change. Methods: We assessed behavior-specific intrinsic motivation using validated scales, from pregnancy up to six time points through 30 months post partum, among diverse cohort participants (N = 311) in a large health care system. Weight was prospectively ascertained via electronic health records, remote scales, and study visits. Results: In adjusted regressions, participants with higher intrinsic motivation experienced significantly reduced postpartum weight. For healthy eating motivation, each one-unit-higher score predicted up to −3.43 lb (95% CI: −5.34 to −1.53) postpartum weight at 24 months; for physical activity motivation, −2.70 lb (95 CI: −4.61 to −0.78) at 30 months; for self-weighing motivation, −4.15 lb (95% CI: −6.33 to −1.97) at 30 months; and, for a combined motivation score across all three behaviors, −5.47 lb (95% CI: −7.95, −2.99) at 24 months. Conclusions: Greater intrinsic motivation for healthy lifestyle behaviors predicted reduced long-term postpartum weight and could be a promising target for innovative behavioral interventions.