I think based on the information, his body is in positive nitrogen balance. Positive nitrogen balance is associated with periods of growth, hypothyoidism, tissue repair, and pregnancy. It means that the intake of nitrogen into the body is greater than the loss of nitrogen from the body, therefore, there is an increase in the total body pool of protein. Nitrogen is an important element in the body; for example all amino acids contain nitrogen and are building blocks that make up the proteins.