A major new systematic review, published by Obesity Reviews in November 2025, has identified the most consistent maternal, paternal and infant factors linked to childhood obesity in the first 1,000 days of life.

Conducted by an international team of experts from the Early Nutrition and Long-Term Health Task Force at ILSI Europe, the review provides the most comprehensive and up-to-date evidence base to support early-life obesity prevention strategies worldwide.

Extensive global analysis

The researchers screened more than 17,000 publications and analysed 177 studies – including data from over 1.8 million children across 37 predominantly high-income countries. The average childhood obesity prevalence reported across these studies was 11 percent.

In total, the team identified 23 risk factors consistently associated with a higher likelihood of childhood obesity.

The strongest risk factors

The review highlights several early-life influences with the greatest impact:

• Maternal health: Higher maternal pre-pregnancy weight, excessive gestational weight gain and smoking during pregnancy
• Birth and infancy: Higher birthweight, being large for gestational age, lack of breastfeeding and rapid infant weight gain.

Knowledge gaps limiting progress

Despite the breadth of available evidence, the authors report several notable research gaps. These include limited study of paternal factors and the preconception period, as well as a lack of research using non-invasive biomarkers. The review also calls for more standardised data collection to support large-scale meta-analyses and more accurate models for predicting childhood obesity risk.

Opportunities for early prevention

Dr Romy Gaillard, Chair of the expert group, said that the first 1,000 days represent a critical window for action:

“Parents-to-be or parents of newborns are in frequent contact with healthcare workers, and are often motivated to make lifestyle changes that benefit both their own health and the health of their children. Our systematic review provides the most comprehensive overview of family-based risk factors for childhood obesity from preconception to two years of age.”

She added that improved early-life risk assessment, supported by advanced modelling, could help target prevention strategies more effectively.

Co-author Dr Janna A van Diepen said:

“Childhood obesity is an urgent and escalating concern. Early identification of risk factors and biomarkers is essential for the development of timely and effective interventions.”

Implications for the food and nutrition sector

The findings reinforce the increasing importance of early-life nutrition, maternal health and targeted family-based interventions in shaping long-term health outcomes. As policymakers and health professionals intensify efforts to curb rising childhood obesity rates, evidence such as this could guide more precise and effective prevention strategies from the start of life onwards.