Do buddhist have any food rules?

Not really. Some Buddhists choose not to eat meat in accordance with the idea of not killing, but this isn't compulsory. It is okay to eat meat, just not to order it directly from the butchers, as this may lead to an animal being killed specifically for you.

I'm a Buddhist and a vegetarian, but I'm not vegetarian because of my religion, it's just a separate thing for me.