Dietary treatment postpartum in women with obesity reduces weight and prevents weight gain: a randomised controlled trial

BACKGROUND: Women with pre-pregnancy obesity have an increased risk of retaining or gaining weight postpartum and may benefit from weight loss treatment. However, evidence is lacking for weight loss strategies in women with BMIs in the higher obesity classes. A dietary treatment for postpartum weight loss resulted in a 10% weight reduction in lactating women with a mean BMI of 30 kg/m(2). We aimed to examine the effects of this dietary treatment on changes in weight, markers of lipid and glucose metabolism, waist and hip circumference and postpartum weight retention (PPWR) in postpartum women with higher BMIs than tested previously. METHODS: At baseline, approximately 8 weeks postpartum, 29 women with a mean (SD) BMI = 40.0 (5.2) kg/m(2) were randomised to a 12-week dietary treatment (n 14) or to a control treatment (n 15). Measurements were made at baseline and after 3 and 12 months. Data was analysed using mixed model. RESULTS: The mean weight change in the diet group was -2.3 (3.1) kg compared to 1.7 (3.1) kg in the control group after 3 months (P = 0.003) and -4.2 (5.6) kg compared to 4.8 (11.8) kg in the control group after 12 months (P = 0.02). The dietary treatment led to reduced waist circumference (P < 0.04) and PPWR (P < 0.01) compared to the control treatment at both time points. The treatment lowered fasting blood glucose at 12 months (P = 0.007) as the only effect on markers of lipid and glucose metabolism. CONCLUSION: The dietary treatment postpartum reduced weight and prevented weight retention or weight gain in women with obesity. TRIAL REGISTRATION: The trial was retrospectively registered at ClinicalTrials.gov (NCT03579667) 06/07/2018. GRAPHICAL ABSTRACT: In a randomised, controlled trial, 29 postpartum women with obesity were allocated to a dietary treatment or a control treatment. The dietary treatment reduced weight and prevented postpartum weight retention or weight gain after 12 months. Reference: Adapted from “Randomized, Placebo-Controlled, Parallel Study Design (2 Arms, Graphical)”, by BioRender.com (2022). Retrieved from https://app.biorender.com/biorender-templates. [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12884-023-05976-w.