They had less strength and stamina that the meat-eaters too/
When India started their vegetarian way of like their military never won another battle, let alone another war. Meat is the source of muscle. Muscle is the source of strength. Doesn't take a rocket scientist...
Some of the earliest Greeks were vegetarians. Hah, I bet Leonidas and his 300 Spartans who gave the Persians a run for their money weren't vegetarians.
In the Middle Ages, peasants were not allowed to hunt. The deer belonged to the Kind, for the King's table. The knights at meat, the peasants mostly didn't.
Watch the documentary “Fat Head”. So many docs on there advocating good animals fats and protein and cutting carbs.
One talked about how he was a vegetarian for 9 years, and a strict one for 3, at the same time he was a strength coach, and he noted that that was when he was the weakest in his life. He also got depressed. Lack of animal fats and protein can cause depression. At the same time in the 80s when vegetarianism was being pushed there was a big rise in the number of books dealing with depression.
The Iliad gives repeated descriptions of warriors roasting meat and offering the first portion to the gods. Same with wine. The wine (heavier than modern wine) went into their bowls, water was added, then a bit was allowed to fall to the ground for the gods’ portion. Then they feasted. Not a vegetarian among ‘em.
I went vegan as part of Gerson therapy last summer because of a cancer diagnosis. My husband, a professional firefighter and serious powerlifter, went vegetarian to support me. Both of us have noticed increased stamina and we’ve had absolutely no trouble building (maintaining for me) muscle mass. I also love how much my skin glows. I hardly wear makeup anymore. Just some eyeshadow, mascara, and lip gloss and I’m done. I’ve always had thick hair, but my stylist is thinning it out so much more, and much more often. She even asked me what I was doing because she noticed a difference. I don’t know what the vegans and vegetarians you teach are doing, but they’re doing it wrong, lol!