If you have IBS, you need a colon cleanse that has a formula with activated charcoal, bentonite clay,and soothing herbs. TVS has a "bentonite clay", but drug people used it for urine tests to pass. It detoxes drug residue according to TVS store sagas and gossip.
Fiber is never wrong or "too much", if accompanied with enough water. Americans are dehydrated and demineralized like their foods! American's are under the 30 grams a day of fiber, you need minimum, both water soluble and insoluble.
People that live in the bush, from Africa, 30 minutes after they eat, most have a bowel movements. Of course this is the meal hours ago. My friend told me that African people in the bush are regular as clockwork. They do not get direticulitus and other bowel disease except for diarrehia and dehydration deaths. In USA we have saline IV's, that prevent that death from dehydration.
There is another factor with high fiber diet, you will have a bowel movement for every meal you eat. That is ideal for human health!
You may not have IBS from enzyme deficiency but a toxin reaction from foods. It could be a fungal toxin in wheat, corn, soy or other grains. You could some food allergy due to unintentional chronic dehydration. Eat the same foods every day and you could become allergic. I ate wheat flour products every day for year and I did not drink enough water!