Bland, fluids. Assuming it is true "food poisoning" (gastroenteritis), not active inflammatory disease, etc., brat diet, bananas, rice (white), applesauce, tea, toast; fluids, not just h2o. Go easy on fruit juices (sorbitol content can cause cramps, diarrhea); miso soup, broths. Add boiled, broiled chicken, fish; baked/boiled potato. Fever, bleed, pain, xs vomit, diarrhea, prolonged course, complex pmh, see md.
Very little. It is important to keep up your electrolytes when you have food poisoning. If you are not vomiting, eat bland foods that are binding. Bananas are excellent for this. Lots of fluids are important to keep hydrated, coconut water is also an excellent natural choice. I would also take a lot of probiotics to replenish the good bacteria. Avoid dairy totally as this will make matters worse.