I have periods where I have symptoms of ibs. Is this a food intolerance, what to do?

Food intolerances fi. Keep a journal of what you are eating especially in proximity to the symptoms, don't forget over the counter medications. Food intolerances like lactose, fructose, sorbitol, nonabsorbable Cellulose found in some vegetables and even trehalose!-yes there is such a thing. Spend some time with your provider so you can exchange all the clues and this help confirm the suspicion of a food infolerance.