Intrinsic motivations for healthy lifestyle help reduce postpartum weight

“[W]e found that intrinsic motivations for engaging in healthy eating, physical activity [PA], and self-weighing lifestyle behaviours are prospectively associated with reduced long-term postpartum weight in a diverse sample,” the researchers said. 

In this study, researchers used validated scales to assess behaviour-specific intrinsic motivation from pregnancy up to six time points through 30 months postpartum among 311 participants in a large healthcare system. In addition, the prospectively ascertained weight using electronic health records, remote scales, and study visits.

Postpartum weight significantly decreased among women with higher intrinsic motivation in adjusted regressions. [Obesity 2025;33:927-935]

For healthy eating motivation, each 1-unit score increase prospectively correlated with up to –3.43 lb (95 percent confidence interval [CI], –5.34 to –1.53) postpartum weight at 24 months. For PA and self-weighing motivations, the corresponding values were –2.70 lb (95 percent CI, –4.61 to –0.78) and –4.15 lb (95 percent CI, –6.33 to –1.97) at 30 months.

For the combined motivation score across all three behaviours, each 1-unit-higher score predicted up to –5.47 lb (95 percent CI, –7.95 to –2.99) postpartum weight at 24 months.

“Lifestyle behaviours impact postpartum weight, yet intrinsic motivation for them (ie, what individuals enjoy, value, and do with ease) is poorly understood,” the researchers said.

“The effect of intrinsic motivation on long-term postpartum weight change may be clinically meaningful,” they noted.

Long-term risk

Women with greater postpartum weight change had increased long-term risks for obesity, suboptimal cardiometabolic health, and adverse pregnancy outcomes in future pregnancies. However, attaining one’s prepregnancy weight may prevent these conditions.

"The present study suggests that intrinsic motivation could be a promising target for novel interventions to reduce long-term postpartum weight and improve maternal health,” the researchers said. 

“Similar approaches have been tested in nonmaternal samples of women engaged in behavioural weight-management trials,” they added.

For instance, a previous study examined the “Stability Skills First” intervention, which sought to increase intrinsic motivation for engaging in healthy lifestyle behaviours by maximizing immediate, day-to-day satisfaction with them. Participants in the intervention arm experienced significantly greater weight loss after 1 year. [J Consult Clin Psychol 2013;81:336-346]

Similarly, greater intrinsic motivation correlated with improved long-term maintenance weight loss in other intervention trial settings. Moreover, autonomous motivation was found to mediate greater weight loss among adults with obesity or overweight. [JAMA 2024;332:21-30]

“Building on these trials, postpartum interventions could be designed to enhance enjoyment of healthy lifestyle behaviours, reduce feelings of deprivation when engaging in healthy behaviours, and address notable uneasiness with self-weighing,” the researchers said.

Future interventions must be developed in a way that lessens emotional reactivity to the scale. This may be done by reframing it as a “neutral tool to support adaptive and sustainable health practices.” [Ann Behav Med 2013;45:s57; Consult Clin Psychol 2013;81:336-346]

“The present study emphasizes the potential utility of addressing intrinsic motivation in novel interventions and demonstrates validated approaches to measure it efficiently in large research samples,” the researchers said.