OBJECTIVE: In our randomized controlled trial, we investigated the impact of healthy eating (HE) aiming for restricted gestational weight gain (GWG) and physical activity (PA) interventions on maternal and neonatal lipid metabolism. RESEARCH DESIGN AND METHODS: Obese pregnant women (n = 436) were included before 20 weeks' gestation and underwent glucose testing (oral glucose tolerance test) and lipid profiling at baseline and 24-28 and 35-37 gestational weeks after an at least 10-h overnight fast. This secondary analysis had a factorial design with comparison of HE (n = 221) versus no HE (n = 215) and PA (n = 218) versus no PA (n = 218). Maternal changes in triglycerides (TG), LDL cholesterol, HDL cholesterol, free fatty acids (FFAs), and leptin from baseline to end of pregnancy and neonatal outcomes were analyzed using general linear models with adjustment for relevant parameters. RESULTS: At 24-28 weeks' gestation, FFAs (mean ± SD, 0.60 ± 0.19 vs. 0.55 ± 0.17 mmol/L, P < 0.01) were increased after adjustment for FFA at baseline, maternal age, BMI at time of examination, gestational week, insulin resistance, self-reported food intake, self-reported physical activity, and maternal smoking, and GWG was lower (3.3 ± 2.6 vs. 4.3 ± 2.8 kg, P < 0.001, adjusted mean differences -1.0 [95% CI -1.5; -0.5]) in HE versus no HE. Fasting glucose levels (4.7 ± 0.4 vs. 4.6 ± 0.4 mmol/L, P < 0.05) and 3-β-hydroxybutyrate (3BHB) (0.082 ± 0.065 vs. 0.068 ± 0.067 mmol/L, P < 0.05) were higher in HE. Significant negative associations between carbohydrate intake and FFA, 3BHB, and fasting glucose at 24-28 weeks' gestation were observed. No differences between groups were found in oral glucose tolerance test or leptin or TG levels at any time. Furthermore, in PA versus no PA, no similar changes were found. In cord blood, elevated FFA levels were found in HE after full adjustment (0.34 ± 0.22 vs. 0.29 ± 0.16 mmol/L, P = 0.01). CONCLUSIONS: HE intervention was associated with reduced GWG, higher FFAs, higher 3BHB, and higher fasting glucose at 24-28 weeks of gestation, suggesting induction of lipolysis. Increased FFA was negatively associated with carbohydrate intake and was also observed in cord blood. These findings support the hypothesis that maternal antenatal dietary restriction including carbohydrates is associated with increased FFA mobilization.