Ages 9 and Older. Protein requirements for children ages 9 and older vary based on the child’s age and gender. The Institute of Medicine encourages children ages 9 to 13 to eat at least 34 grams of protein every day; girls ages 14 to 18 need 46 grams of protein; and boys ages 14 to 18 require at least 52 grams of protein each day.