Parenthood takes a toll on waistlines: Study reveals impact of diet and activity on postpartum weight changes

By Tarun Sai LomteReviewed by Benedette Cuffari, M.Sc.Jun 21 2023

A recent study published in Frontiers in Public Health examines diet, sedentary behavior (SB), and physical activity in couples and how these factors relate to changes in body mass index (BMI) during the transition to parenthood.

Study: Dietary intake, physical activity and sedentary behavior and association with BMI during the transition to parenthood: a prospective dyadic study. Image Credit: Starocean / Shutterstock.com

Weight changes in new parents

Healthy dietary patterns, lower SB, and adequate PA during pregnancy can lead to beneficial health outcomes for the mother and child. A healthy diet and regular PA can also help postpartum females lose weight gained during pregnancy and prevent weight retention.

During the transition to parenthood, parents are at an increased risk of unfavorable body weight changes. However, there remains a lack of data on whether these body weight or composition changes are linked to changes in energy balance-related behavior (EBRB).

About the study

In the present study, researchers investigate EBRB changes in parents from pregnancy to six months postpartum and how these relate to BMI changes. Expectant nulliparous couples were recruited from June to December 2018 from four hospitals in Belgium.

Baseline measurements were obtained at the end of the first trimester. Follow-up measurements were acquired six weeks and six months postpartum.

During each visit, researchers obtained anthropometric measurements and provided participants with accelerometers. Participants were instructed to wear accelerometers for at least 12 hours daily for one week after anthropometric measurements and keep records of their activity when not wearing the device. From this data, time spent on light-intensity (LIPA) or moderate-to-vigorous PA (MVPA) was estimated.

One week after the visit, participants completed an online questionnaire on sociodemographics, diet, and child-feeding practices. The 22-item food frequency questionnaire assessed dietary intake over the past month. Sociodemographics were evaluated at baseline, and information on exclusive breastfeeding was acquired.

Data on neonatal sex, gestational age, and mothers’ last recorded weight before delivery were obtained from medical records. The primary objective of the study was to investigate EBRB changes, whereas the secondary aim was to determine how BMI changes were associated with EBRB changes over time. Data were analyzed using dyadic longitudinal analytic methods.

Study findings

The researchers initially screened 152 couples at baseline and included 144 for analysis. Females with a miscarriage, in vitro fertilization, or a history of bariatric surgery and their partners were excluded. Fifteen females and 17 males were removed from the study due to a lack of follow-up data.

Overall, females significantly reduced their fruit intake and increased alcohol consumption from baseline to postpartum. A trend toward a significant increase in energy intake was observed at six months postpartum relative to baseline.

In males, significant reductions in alcohol consumption were observed at six months postpartum relative to baseline. Males and females exhibited significant differences in SB and PA at postpartum time points as compared to their baseline values.

Females had significantly increased LIPA at six weeks and six months postpartum. At six weeks postpartum, lower MVPA and SB were observed in females.

Males significantly increased LIPA by six months postpartum and reduced MVPA relative to baseline, with no significant changes in SB.

BMI changes from six weeks to six months postpartum were negatively associated with changes in fruit intake in females. Each €1,000 increase in monthly household income was associated with a decrease in the average BMI by 0.18 kg/m². A negative trend was observed between BMI and fruit intake changes in males.

Conclusions

Mothers reduced fruit consumption but increased alcohol intake from pregnancy to six months postpartum; however, there were no changes in vegetable intake and total energy intake. Maternal LIPA increased over time, whereas MVPA was lower at six weeks postpartum until ultimately returning to baseline levels by six months postpartum. Maternal SB was significantly lower postpartum.

Changes in dietary intake were not observed in males during the transition to parenthood. However, paternal LIPA increased at six months postpartum, while MVPA decreased relative to baseline. There were no significant differences in paternal SB over time.

Maternal BMI changes were positively associated with gestational weight gain and negatively associated with household income and daily fruit intake changes. BMI changes were not associated with PA or SB changes in either parent.

Taken together, the study findings have implications for designing and delivering lifestyle interventions during pregnancy and postpartum. Policymakers, healthcare providers, and researchers could utilize these results to adequately support parents for healthy lifestyles by implementing multi-level couple- or family-focused approaches.