WebMD states that the amount of protein a person needs each day varies based on age and gender. Generally, 10 to 35 percent of the daily caloric intake should be derived from protein.
WebMD further explains that babies need 10 grams of protein per day. School age children require 19 to 34 grams per day, teenage boys need up to 52 grams per day and teenage girls require 46 grams per day. Adult men need approximately 56 grams of protein per day and adult women only need 46 grams per day. Pregnant or nursing women require 71 grams of protein per day.