The composition of breast milk is a great starting point for our understanding of kids’ macronutrient needs. The macronutrient ratio of human breast milk is quite variable, and may even change based on a baby’s specific needs.
BREAST MILK RATIO
Carbohydrates — 57% to 70%. Fat — 28% to 39% Protein — 7% to 10%
The USDA used this information to establish a baby’s macronutrient guidelines: