Top tier female athletes tend to do exactly that. Breasts are mostly fat. Look at the women gymnasts, runners, swimmers, soccer players, etc. The ones with generous curves are the exceptions. I suppose everything grows back when they retire and put on 20 pounds.
I went to a gymnastics event back in college, and was truly amazed when there was a competitor there that was naturally very endowed... Far larger chest than any Gymnast I had ever seen. She competed fine, and was a very fit woman... but very busty.
She competed well, but it was surprising to see... definitely stood out among the crowd... Never seen a gymnast like that before or since.