Sugar Intake in Early Childhood Linked to Different Body Fat Outcomes in Boys and Girls: Study

Could sugar consumed during pregnancy influence a child's body fat differently in boys and girls? A new study suggests that the timing of sugar exposure may be linked to body fat development during the first two years of life.

Published on the medRxiv preprint server, the study was conducted by researchers at the University of Kansas Medical Center and the University of Kansas.

Researchers examined dietary information from 130 mother-child pairs, including 65 boys and 65 girls, to investigate associations between added sugar and fructose intake during pregnancy, infancy and toddlerhood.

Maternal diets were assessed during pregnancy, while children's food intake was recorded up to two years of age.

At 24 months, researchers measured waist circumference and skinfold thickness. Body composition scans were available for only 42 children.

The findings suggested that higher maternal added sugar intake during pregnancy was more strongly associated with increased total and regional body fat in girls than in boys.

However, prenatal fructose consumption showed a stronger association with waist circumference in boys.

During infancy, higher added sugar intake was more strongly linked to overall and regional body fat in boys than girls.

Researchers also observed that fructose intake during infancy was associated with greater fat-free mass in girls, which includes muscle, bone and other non-fat tissues.

Associations during toddlerhood were less convincing, with some results failing to reach statistical significance.

Importantly, the study did not establish that dietary sugars directly caused increased body fat.

Researchers highlighted limitations including the small sample, reliance on dietary recalls and limited availability of body composition scans.

The findings suggest that early sugar exposure may relate differently to body composition depending on developmental stage and sex, but larger studies are needed. The research has not yet undergone peer review.

REFERENCE: Preliminary scientific report. Fortin-Miller, S. A., et al. (2026). Sex-Specific Associations of Added Sugars and Fructose Exposure Across the First 1,000 Days With Body Composition at 24 Months. medRxiv. DOI: 10.64898/2026.10.16.26365755.