To figure out what ancient warriors ate, the researchers examined the remains of 22 gladiators using stable carbon and nitrogen isotope analysis. The article is a little on the anthropological side, but it is a very good look at ancient nutrition and compares them to modern methods.
http://www.npr.org/blogs/thesalt/20...de-ancient-athletes-also-had-a-recovery-drink
http://www.npr.org/blogs/thesalt/20...de-ancient-athletes-also-had-a-recovery-drink