How do i know if i have food intolerance?

Elimination of foods: The best , least expensive, and most reliable way is to remove something from your diet for a week or two...See how you feel...Then reintroduce it and see if you feel worse. You can also get allergy testing...Which will tell you if you have acute histamine related allergies (like hives, trouble breathing). There is another path for food intolerance that is hard to test for. Look at alcat.Com test.