A European clinical trial found that lowering milk protein in toddler formula did not lead to a lower body mass index (BMI) at age two, according to an April 15 announcement. The Toddler Milk Intervention (ToMI) trial, published in Clinical Nutrition, involved over 1,600 healthy children from Spain and Germany who were randomly assigned either a low-protein or high-protein isocaloric formula between ages one and two.
The study matters because childhood obesity remains a significant public health concern. Understanding how early nutrition influences growth could help shape future dietary guidelines for toddlers.
Researchers observed no statistically significant difference in BMI z-scores between the groups at 24 months. However, children given higher-protein formulas showed greater increases in weight and length compared to World Health Organization standards. This suggests that while reducing protein may not affect BMI by age two, it can influence other aspects of growth during toddlerhood.
The ToMI trial builds on previous findings such as the Childhood Obesity Prevention (CHOP) study, which linked high infant protein intake with increased obesity risk later in childhood through mechanisms like the Early Protein Hypothesis involving branched-chain amino acids and mTOR pathway activation. Despite changes in diet as toddlers begin eating more solid foods after infancy, milk products still contribute about half of their total protein intake.
Guidelines recommend moderate dairy consumption for young children—typically around 300 to 500 milliliters per day—but actual intake often exceeds these levels. The ToMI researchers suggest limiting regular milk consumption to about 200 to 400 milliliters daily to avoid unnecessary growth acceleration.
While the intervention did not show lasting effects on BMI by age two, secondary outcomes included transient differences at earlier ages and more stable growth patterns among those receiving less protein. The authors note that further follow-up through age six will be needed to determine if early differences have long-term impacts on adiposity.
