Changes in Diet Quality from Early Pregnancy through 6 Years Postpartum among Women with Overweight and Obesity

14.5.2026

33rd European Congress on Obesity (ECO 2026) – Abstract

Kaya Kacar H, Hieta J, Saros L, Laitinen K.

Introduction: Diet quality during pregnancy and the postpartum years is a key determinant of long-term maternal health and influences the risk of developing chronic diseases. High-quality diets rich in whole grains and essential micronutrients support maternal health, reduce pregnancy complications, and promote fetal growth, while diets high in sugar and saturated fats with micronutrient deficiencies increase risks of obesity and neonatal adiposity. The aim in this study was to investigate changes in diet quality from early pregnancy through 6 years postpartum and to assess whether these changes differed between women with overweight and those with obesity.

Methods: This study was conducted as part of a double-blind, placebo-controlled randomised trial (ClinicalTrials.gov Identifier: NCT01922791). Women were recruited in Southwest Finland during early pregnancy (<18 gestational weeks). Inclusion criteria included a pre-pregnancy body mass index (BMI) ≥ 25 kg/m² and absence of chronic diseases. Diet quality was assessed using the validated Index of Diet Quality (IDQ) questionnaire, which consists of 18 items evaluating the amount and frequency of consumption of whole-grain products, fat-containing foods, dairy products, vegetables, fruits and berries, foods with added sugar, and meal patterns during the preceding week. A linear mixed-effects model was used to examine changes in diet quality across time and maternal BMI category.

Results: In total, 438 women were included in the study. Of these, 266 women (60.7%) had a body mass index (BMI) of 25–30 kg/m² and were classified as having overweight, while 172 women (39.3%) had a BMI ≥30 kg/m² and were classified as having obesity. There was a significant main effect of time, F(6, 237.04) = 6.60, p < 0.001, indicating changes in diet quality over the study period. The main effect of maternal BMI category was not significant, F(1, 320.31) = 1.69, p = 0.194, nor was the BMI × time interaction, F(6, 237.04) = 0.98, p = 0.440. Compared to the final assessment at six years post-partum, diet quality scores were higher at several earlier time points (e.g., late pregnancy: β = 0.75, SE = 0.28, p = 0.007; three months post-partum: β = 0.56, SE = 0.24, p = 0.019). These temporal patterns did not differ by maternal BMI category.

Conclusion: Diet quality among women with overweight or obesity improved during pregnancy and the early postpartum period, but declined over the longer term, with no differences in these patterns across BMI categories. These findings highlight pregnancy as a critical window for improving diet quality and emphasise the need for sustained focus on diet beyond the immediate postpartum period. Interventions that focus on long-term maternal nutrition may be essential for sustaining dietary improvements and reducing the risk of future chronic disease and obesity, particularly among women who begin pregnancy with overweight or obesity.