How can keeping a record of my symptoms and triggers be helpful for treating ibs?

Predict food allergy. The best way to know what is causing the allergy and for treatment is rotation and elimination diet - it helps to keep a journal for body's response there are also tools to diagnose food allergies one of the is zyto testing the other is GI allergix profile from metametrix labs.
IBS can be either . Constipation predominant or diarrhea predominant. By keeping a diary it will help your doctor to decide what symptoms to treat. By keeping a track of triggers you will obviously know what to avoid.