Infant Diet Quality Linked to Obesity Risk at Ages 6 and 9: Study - Video

A large population-based study published in Maternal & Child Nutrition has found that poorer alignment with infant nutrition guidelines during the first year of life is associated with a higher risk of obesity in later childhood.

Researchers analyzed data from 12,848 children born in Iceland between 2009 and 2015, using linked national health registries. The study examined whether the Infant Diet Score (IDS)—a composite measure reflecting adherence to recommended infant feeding practices—was associated with obesity or overweight at ages 2.5, 4, 6, and 9 years.

The IDS includes six components: duration of exclusive breastfeeding, duration of any breastfeeding, timing of introduction of cow’s milk, timing of semi-solid foods, food group variety, and vitamin D supplementation. Children were divided into five quintiles based on their IDS, with higher scores indicating better alignment with infant nutrition guidelines.

At age six, 19.1% of children were classified as overweight and 8% as obese. By age nine, 23% were overweight and 14.6% were obese. The findings showed that children in the two lowest IDS quintiles had a significantly higher risk of obesity at ages six and nine compared to those in the highest quintile (IDS > 4.08). Specifically, children in the lowest quintiles had 37% to 58% greater odds of obesity in later childhood.

Associations were less consistent at younger ages. No clear links were observed between IDS and obesity or overweight at ages 2.5 and 4, except for one lower quintile at age 2.5. Additionally, IDS was not significantly associated with overweight (without obesity) at ages six and nine.

The results suggest that early-life dietary patterns may influence longer-term weight outcomes. However, as an observational registry-based study, the findings do not establish causation. The authors note that environmental, behavioral, and socioeconomic factors later in childhood may also shape obesity risk.

The study highlights the potential public health importance of supporting optimal nutrition during infancy as part of broader childhood obesity prevention strategies.

REFERENCE: Jonsdottir J, Thorisdottir B, Einarsdottir K, Thorsdottir I (2026). Infant Diet Is Associated With BMI Later in Childhood: A Nation-Wide Mother-Child Cohort Study in Iceland (ICE-MCH). Maternal & Child Nutrition, 22(1), e70165. DOI: 10.1111/mcn.70165, https://onlinelibrary.wiley.com/doi/10.1111/mcn.70165