Diet and exercise interventions among overweight and obese lactating women: randomized trial of effects on cardiovascular risk factors.

Objective: To examine the effects of Diet (D) and Exercise (E) interventions on cardiovascular fitness, waist circumference, blood lipids, glucose metabolism, inflammation markers, insulin-like growth factor 1 (IGF-1) and blood pressure in overweight and obese lactating women.
Methods: At 10-14 wk postpartum, 68 Swedish women with a self-reported pre-pregnancy BMI of 25-35 kg/m(2) were randomized to a 12-wk behavior modification treatment with D, E, both or control using a 2×2 factorial design. The goal of D treatment was to reduce body weight by 0.5 kg/wk, accomplished by decreasing energy intake by 500 kcal/d and monitoring weight loss through self-weighing. The goal of E treatment was to perform 4 45-min walks per wk at 60-70% of max heart-rate using a heart-rate monitor. Effects were measured 12 wk and 1 y after randomization. General Linear Modeling was used to study main and interaction effects adjusted for baseline values of dependent variable.
Results: There was a significant main effect of the D treatment, decreasing waist circumference (P = 0.001), total cholesterol (P = 0.007), LDL-cholesterol (P = 0.003) and fasting insulin (P = 0.042), at the end of the 12-wk treatment. The decreased waist circumference (P<0.001) and insulin (P = 0.024) was sustained and HDL-cholesterol increased (P = 0.005) at the 1-y follow-up. No effects from the E treatment or any interaction effects were observed.
Conclusions: Dietary behavior modification that produced sustained weight loss among overweight and obese lactating women also improved risk factors for cardiovascular disease and type 2 diabetes. This intervention may not only reduce weight-related risks with future pregnancies but also long-term risk for metabolic disease.
Trial Registration: ClinicalTrials.gov NCT01343238.