But actually, the diet plan for IBS is the same for IBS diarrhea (or IBS D) as for IBS constipation (or IBS C). Why?

Because both IBS D and IBS C result from the same underlying pathology. IBS is defined as a brain-gut disorder.

It is a dysfunction of the enteric nervous system of the gut and the way that enteric nervous system interacts with the brain.

Interestingly, the enteric nervous system is also called your second brain.

Whether you have IBS diarrrhea, constipation, or both, your bowel motility is dysfunctional. You don't have a disease, you have a disorder.

This brain-gut disorder causes colon contractions, or peristalsis, that are too fast, too strong, too slow, too weak, or irregular and mis-timed.

If your bowel motility is too fast and strong, it results in urgency and IBS diarrhea, and often spasms and pain.

If your motility is too slow or irregular, it results in IBS constipation, and often bloating and trapped gas.

IBS can also manifest as a nasty combination of all these symptoms, with gut motility so wildly dysfunctional that you alternate between diarrhea and constipation.

This is also called IBS A for alternating, or IBS M, for mixed diarrhea/constipation.

Regardless of the specific IBS symptoms, the diet plan is the same. How can that be?

Because your goal is always stable, rhythmic, normal bowel contractions, which in turn will result in normal bowel function.

The dietary plan for achieving this is based on regulating your bowel function from either extreme, diarrhea and/or constipation, to a stable middle point.

Your Keys to Motility Stability

The diet keys to IBS stability are:

1. A foundation of green light soluble fiber safe foods

2. Adding onto that foundation as needed with a slowly fermenting prebiotic soluble fiber supplement

3. Cautious incorporation of yellow light insoluble fiber foods

4. Avoidance of red light IBS trigger foods

5. Adding natural antispasmodics and carminatives as needed for pain, bloating, gas

IBS Trigger Foods

One big problem is that it isn't a single food that triggers IBS symptoms.

It's ANY food that is high in fat, insoluble fiber, caffeine, coffee (even decaf), carbonation, or alcohol. Why?

Because all of these food categories are either GI stimulants or irritants, and can cause violent reactions of your gastrocolic reflex.

This directly affects the muscles in your colon and can lead to IBS pain, constipation AND diarrhea, gas, and bloating. These are the IBS diet trigger foods.

But! The happy truth is that eating safely for IBS does not mean deprivation, never going to restaurants, bland food, or an unhealthily limited diet. Nor does it mean living on "rabbit food" available exclusively at health food stores, or following brutal elimination diets, or keeping endless IBS food diaries for the rest of your life.

It does mean learning to eat safely by realizing how different foods physically affect the GI tract. And then managing how foods can help or hurt both IBS diarrhea AND constipation, as well as bloating, gas, nausea, and painful abdominal cramps.

Following the Irritable Bowel Syndrome diet simply means learning how foods can prevent or trigger a spastic colon.

Please remember, you are not alone!

An estimated 15-20% of all Americans have IBS, and it's a devastating, incurable condition. But you can use your diet to successfully manage all symptoms.



Take immediate control of your IBS symptoms with Heather's IBS diet kit...


Read on to learn all about your soluble fiber safe foods...



By Heather Van Vorous, 2/25/25