Effectiveness of a weight loss intervention in postpartum women: results from a randomized controlled trial in primary health care.

BACKGROUND: Reproduction has been identified as an important factor for long-term weight gain among women. A previous efficacy trial has successfully produced postpartum weight loss; however, the effectiveness of this intervention needs to be established. OBJECTIVE: This study was designed to evaluate the short- and long-term effectiveness of a diet behavior modification treatment to produce weight loss in postpartum women within the primary health care setting in Sweden. DESIGN: During 2011-2014, 110 women with a self-reported body mass index (BMI; in kg/m(2)) of ≥27 at 6-15 wk postpartum were randomly assigned to the diet behavior modification group (D group) or the control group (C group). Women randomly assigned to the D group (n = 54) received a structured 12-wk diet behavior modification treatment by a dietitian and were instructed to gradually implement a diet plan based on the Nordic Nutrition Recommendations and to self-weigh ≥3 times/wk. Women randomly assigned to the C group (n = 56) were given a brochure on healthy eating. The primary outcome was change in body weight after 12 wk and 1 y. The retention rate was 91% and 85% at 12 wk and 1 y, respectively. RESULTS: At baseline, women had a median (1st, 3rd quartile) BMI of 31.0 (28.8, 33.6), and 84% were breastfeeding. After 12 wk, median weight change in the D group was -6.1 kg (-8.4, -3.2 kg) compared with -1.6 kg (-3.5, -0.4 kg) in the C group (P < 0.001). The difference was maintained at the 1-y follow-up for the D group, -10.0 kg (-11.7, -5.9 kg) compared with -4.3 kg (-10.2, -1.0 kg) in the C group (P = 0.004). In addition, the D group reduced BMI, waist circumference, hip circumference, and body fat percentage more than did the C group at both 12 wk and 1 y (all P < 0.05). CONCLUSION: A low-intensity diet treatment delivered by a dietitian within the primary health care setting can produce clinically relevant and sustainable weight loss in postpartum women with overweight and obesity. This trial was registered at clinicaltrials.gov as NCT01949558.