Well, the only logic to that would be if she was of the age of maturation, then increasing the amount of protein in the body will be beneficial to the tissue construction process... in the sense that the building materials will be at hand. And the formation of fat from protein is incurred only with ample sugar serum levels. Without necessary sugars, protein is more apt to forming/repairing muscle tissues. However, a little body fat isn't such a bad thing considering the breasts will receive a large percentage of that fat, regardless of age. Also, iirc the female body releases larger amounts and differing types of hormones if a certain percentage of body fat is maintained (hormones beneficial to secondary sex characteristics, including breast development). Can't remember the number exactly, but I think it's between 15%-20%.
