Sampling the local cuisine is part the travel experience. While I enjoy the food on the ship it is hardly "native". I know my body and try to avoid things I know will effect my stomach, however it's really just about always a crap shoot. You could eat something at home that may make you sick. I just bring a couple of "tummy aids" with me and hope for the best. I've only gotten sick while traveling once about 20 years ago so I guess I'm lucky.