Because meat was usually reserved for sacrifices to the gods, not part of the daily diet, introducing meat into an athlete's diet was especially significant, Stocking said. There's a story about a wrestler named Milo of Croton who was known for gaining his strength by lifting a calf every day until it was a full-grown bull. The story goes that he carried it around the Olympic stadium -- and then ate it.
"It's probably not true, but it shows the value of meat," Stocking said. "For an athlete to eat a whole bull shows their level of power and status."
Other ancient writing shows that a low-carb, gluten-free diet may have been recommended.
"A lot of ancient writers wrote that for optimal physical performance, athletes should avoid grains and breads for six months before the Olympics," Segan said.
Fragments of other documents suggest that athletes may have consumed diets rich in fish, legumes, chickpeas, olives, some types of cheese and dried fruit -- what we would call a Mediterranean diet, she said.
Not everything has a modern-day equivalent. Ancient athletes appear to have believed that olive oil was "good for you inside and out," Segan said. At early Olympics, athletes "would coat their body in olive oil and compete nude. So only males and unmarried women were allowed to watch."
They also may have relied on wine more than water, since alcohol kills germs that could taint water.
"Hippocrates had a great recipe for athletes with sore muscles: Get drunk twice in the period of a day and have sex," Segan said. "I asked my own doctor what that was about, and he said, well, if you hurt your back I would prescribe a muscle relaxant -- alcohol and sex can also relax muscles."