Preventing Childhood Obesity: Strategies for the First 1,000 Days

A 2025 narrative review published in Pediatric Obesity examined the effectiveness of preventive interventions for childhood obesity initiated during the first 1,000 days of life—from conception through a child’s second birthday. The review focused on randomized controlled trials (RCTs) and systematic reviews that implemented strategies during pregnancy, infancy, and early toddlerhood.

The authors conducted a structured search of English-language studies published between 2012 and 2023. A total of 37 unique RCTs and 9 systematic reviews met the inclusion criteria. Studies were evaluated based on the age window of intervention, the delivery setting (e.g., healthcare or community), and primary outcomes, which included BMI z-scores, prevalence of overweight or obesity, and modifiable risk behaviors such as infant feeding and physical activity .

Most trials (57%) began during pregnancy, with the remainder starting during infancy or spanning both time periods. Interventions typically focused on maternal diet and physical activity, breastfeeding promotion, complementary feeding practices, responsive parenting, sleep regulation, and screen time reduction. Delivery modes varied and included in-person counseling, home visits, telephone calls, mobile apps, and educational materials .

Among the pregnancy-focused interventions, 12 out of 21 trials reported statistically significant effects on child adiposity outcomes. These interventions commonly targeted maternal weight gain, dietary habits, and gestational diabetes management. For example, several studies demonstrated reduced offspring BMI z-scores or lower risk of high birth weight when mothers received structured lifestyle counseling during pregnancy .

Infancy- and toddlerhood-focused interventions showed more variability in outcomes. Of the 16 trials initiated postnatally, 9 reported significant reductions in child adiposity or improvements in feeding behaviors. Interventions emphasizing responsive feeding and sleep routines were associated with modest improvements in weight-related measures. However, some studies that delivered information-only interventions, particularly those using digital platforms without personal contact, reported limited effects .

Several multicomponent interventions that spanned both pregnancy and infancy reported improvements in behavioral outcomes, such as prolonged breastfeeding duration or delayed introduction of solid foods, even when changes in BMI were not observed. Notably, interventions that involved repeated contacts and multidisciplinary teams across healthcare settings were more likely to report significant effects .

Despite these findings, the authors noted considerable heterogeneity in study design, duration, outcome measures, and target populations. This variability limited the ability to draw conclusions about the comparative effectiveness of different intervention strategies. Furthermore, many studies were conducted in high-income countries and may not be generalizable to other settings .

The review concludes that interventions initiated in the first 1,000 days can influence early risk factors for childhood obesity, particularly when delivered in healthcare settings with consistent engagement. However, long-term follow-up data and standardized outcome measures are needed to evaluate the sustained impact of these strategies across diverse populations.