In 1909, Jack London wrote A Piece of Steak; an aging boxer, Tom King, loses a critical match because he is too poor to buy a piece of steak to give him power: for want of a piece of steak, a boxing match was lost. LINK
As a su-veg martial artist, I have always doubted this. I practiced martial arts for over 15 years before I dropped all animal products from my diet, and immediately found my power and stamina markedly improved.
Where did Chinese martial arts come from? From the “fighting monks” of 少林寺Shaolin temple; the su-veg diet is Buddhist (no animal products, no garlic, leeks, onions). Don’t try to tell me that monks in such a strict temple did not 守戒follow the precepts!
An interesting archeological find shows what Roman gladiators ate: mainly beans and grain, not meat. Romans called gladiators hordearii, meaning they ate barley. LINK
Put down Tom King’s loss rather to that pipe he was smoking, which robbed him of his wind.