In IBS it is best to avoid certain foods till you are well on the way to reversing it. Raw food is to be avoided initially as it is high in fibre and can irritate the bowel. To reverse IBS, you will need to first remove all the irritants like dairy, animal products and packaged foods from your diet.
When you switch to a whole food plant-based diet, your bowel will heal and you can begin to consume raw foods very slowly, beginning with foods that are easily accepted by the body. Sometimes, you could start with just bananas or green smoothies and then gradually increase by adding different foods, one at a time.