Preconception lifestyle intervention reduces long term energy intake in women with obesity and infertility: a randomised controlled trial.

Background: The preconceptional period may be an optimal window of opportunity to improve lifestyle. We previously showed that a 6 month preconception lifestyle intervention among women with obesity and infertility was successful in decreasing the intake of high caloric snacks and beverages, increasing physical activity and in reducing weight in the short term. We now report the effects of the preconception lifestyle intervention on diet, physical activity and body mass index (BMI) at 5.5 years (range = 3.7-7.0 years) after the intervention.

Methods: We followed women who participated in the LIFEstyle study, a multicentre RCT in which women with obesity and infertility were assigned to a six-month lifestyle intervention program or prompt infertility treatment (N = 577). Diet and physical activity 5.5 years later were assessed with an 173-item food frequency questionnaire (N = 175) and Actigraph triaxial accelerometers (N = 155), respectively. BMI was calculated from self-reported weight and previously measured height (N = 179). Dietary intake, physical activity, and BMI in the intervention and control group were compared using multivariate regression models. Additionally, dietary intake, physical activity and BMI of women allocated to the intervention arm with successful weight loss during the intervention (i.e. BMI < 29 kg/m or ≥ 5% weight loss), unsuccessful weight loss and the control group were compared with ANCOVA.

Results: Although BMI did not differ between the intervention and control group 5.5 years after the intervention (- 0.5 kg/m [- 2.0;1.1]; P = 0.56), the intervention group did report a lower energy intake (- 216 kcal/day [- 417;-16]; P = 0.04). Women in the intervention arm who successfully lost weight during the intervention had a significantly lower BMI at follow-up compared to women in the intervention arm who did not lose weight successfully (- 3.4 kg/m [- 6.3;-0.6]; P = 0.01), and they reported a significantly lower energy intake compared to the control group (- 301 kcal [- 589;-14]; P = 0.04). Macronutrient intake, diet quality, and physical activity did not differ between the intervention and control group, irrespective of successful weight loss during the intervention.

Conclusions: In our study population, a preconception lifestyle intervention led to reduced energy intake 5.5 years later. Additionally, women allocated to the intervention group who were successful in losing weight during the intervention also had a lower BMI at follow-up. This shows the potential sustainable effect of a preconception lifestyle intervention.

Trial Registration: This trial was registered on 16 November 2008 in the Dutch trial register; clinical trial registry number NTR1530 .