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

Abstract

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. 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. 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. Greater intrinsic motivation for healthy lifestyle behaviors predicted reduced long-term postpartum weight and could be a promising target for innovative behavioral interventions.