Hilarious. And one of the reasons why I'm skeptical of the pronouncements of doctors for athletic patients. Some doctors keep up and read the journals. Others simply do not. My doctor, a long distance cyclist himself, does read the journals and thankfully knows more about it than I do.

Yes, doctors do write "prescriptions" for both exercise and diet, though they can't be filled at your local pharmacy. For instance:
https://www.seattletimes.com/nation-...of-medication/