I say none of them would be likely to eat meat, other then maybe try it out of curiosity. Meat is unhealthy for a pony, their bodies are not meant to digest it. Unless you say, well my little ponies are different than real ponies...I guess you could argue that, but we have pretty good evidence that at-least most of the ponies in the show don't eat meat. In the human world maybe some of them would, but not in the pony world, even in the human world if you look at the cafeteria food it's all vegetables. I say the most likely is obviously Gilda and the wild animals that are natural carnivorous.
Your statement has alot of faulty logic's. Ponies bodies are made for eating just vegetables. They can't digest meat well, so eating meat would make them sick and could cause damage to their bodies. Strength and energy doesn't come from how much meat you it, it comes from eating healthy, also alot of vegetables have protein too, and horses don't need as much protein as carnivorous animals do to be healthy.
And if you're referring to humans. You'd be surprised, alot of athletes eat a vegetarian diet, because it is healthy. People with a healthy vegetarian diet are less likely to get certain diseases, don't have to worry about getting high food cholesterol that you can only get from eating animal products, they don't have to worry about being over weight, and don't have as many harmful chemicals in their food. You can have a healthy meat diet too, but it is common that meat eaters don't pay enough attention to their diet, like vegetarians and vegans who take extra care.