Write an article based on this "Track everything you eat for at least 2 weeks. Write down everything you eat and drink. Carefully record the timing, type, and severity of reactions. Discuss your findings with a dietitian or health care provider."
If you're unsure which particular foods seem to cause problems for you, keep a food diary for two or more weeks. Having a record of foods and symptoms can help you associate particular foods or ingredients with particular reactions. Once you have an idea of a few foods that may be causing discomfort, you can try elimination diets or formal allergy testing at a health care provider's office. It is essential to have a complete record of everything you consume during the weeks of your food diary.  Continue to eat your regular diet, but carry a small notepad or use the notes function on your smartphone to record snacks, vending machine purchases, and other drinks or bites to eat you may have throughout the day. Include all ingredients. For example, if you eat an oatmeal cookie, write down all ingredients or save the ingredient list if the cookie is store-bought. This will help you pinpoint which food causes issues. You should be able to distinguish between an oat and an egg intolerance by knowing exactly what everything you eat contains and performing an elimination and reintroduction later, as long as it is safe to do so. In some cases, food intolerance can be confused with actual allergic reactions, and temporal reactions may point to the wrong offender foods. Write down the details of symptoms such as itchiness, swelling, hives, stomach discomfort, diarrhea, nausea, cramps, fever, and any other reactions of the skin or gastrointestinal tract. This will help identify the type of sensitivity you have and the management techniques that will be most appropriate for your food intolerance or allergy. Once you have a detailed food diary, you can discuss potential offending foods with a nutrition specialist or allergist to identify particular foods to avoid or strategies to reduce reactions.