Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is an intestinal disorder that causes characteristic symptoms including abdominal pain, cramping, diarrhea, and constipation but without any other signs of another condition causing these symptoms.

  • Overview
  • Action Plan
  • Ask The Doctor
  • Related Info
  • Success Stories
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The prevalence of irritable bowel syndrome (IBS) is approximately 10-15% in the U.S.,1 and most of them haven’t even been diagnosed officially. IBS is more common in females than males. Symptoms of IBS vary from person to person, ranging from mild to severe. Symptoms of IBS may include:

  • Diarrhea/Loose stools
  • Constipation/painful defecation
  • After-meal fecal urgency
  • Alternation between loose stools and constipation, but usually one predominates the other
  • Abdominal pain, often improved after a bowel movement
  • Gas/Bloating
  • Mucus in stool
  • Heartburn
  • Nausea
  • Exaggerated menstrual symptoms
  • Fibromyalgia symptoms (widespread aches and pains)
  • Symptoms exaggerated with stress

The SAD diet, which is predominantly processed foods and animal products, sets the stage for chronic digestive disturbance and unfavorable digestive health. Digestive muscle cramping, bacterial imbalances, and hormonal triggers from conventional foods eventually lead to chronic discomfort and digestive disturbance. The overgrowth of non-favorable bacteria in the intestines, as well as the overall imbalance of intestinal flora, all seem to play a role. Investigators have noted that the more fiber in one’s diet, the better off they are with their IBS symptoms. For some reason which we don’t fully understand, many with IBS report that they are either sensitive to gluten, fructose, and fructans, which are found in a variety of fruits and vegetables. To resolve this problem nutritionally, not only do sufferers need to eat a healthful Nutritarian diet, but many have to avoid wheat, avoid the high fructose fruits, and make the minor adjustments to get the best result. Most can recover in a few months.

  1. Hungin AP, Chang L, Locke GR, et al. Irritable bowel syndrome in the United States: prevalence, symptom patterns and impact. Aliment Pharmacol Ther 2005, 21:1365-1375.

Action Plan


  • A Nutritarian eating style should be the foundational approach to addressing IBS, but in some cases, this alone may gradually improve symptoms over time, so be patient.
  • If symptoms continue or are not fully taken care of while following a Nutritarian eating style, then consider the following:
    • Reduce the intake of moderate-to-high fructan/fructose-containing fruits and vegetables
    • Reduce or eliminate gluten (see Gluten sensitivity)
  • If constipation is the primary symptom, then focus on drinking sufficient amounts of water between meals.
  • Avoid caffeine or other stimulants.
  • Chew all food to a liquid-like consistency before swallowing.

Other Considerations

  • Most people notice a significant improvement in symptoms with the addition of probiotic supplementation and can help speed up the effect of transitioning to a Nutritarian eating style.
  • Seeking psychological care/treatment may help build a strategy for reducing stress, which may be a contributing factor to IBS symptoms

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Ask The Doctor

The following are sample questions from the Ask the Doctor Community Platinum and higher members can post their health questions directly to Dr. Fuhrman. (All members can browse questions and answers.)


I have been following a Nutritarian diet for a little over two years. I have been diagnosed with IBS and have occasional bouts with constipation, and the constipation, bloating, and gas have not stopped.

  1. I have been working on diet issues to try and resolve the gas problem. Considering that methane tends to lengthen transit time, would a product like Beano have any effect on alleviating the constipation?
  2. I noticed fructose, high fructose corn syrup, apples, pears etc. on the FODMAPS list mentioned in the IBS webinar. I don’t use added sugar but do eat the fruit on the list. I also use a lot of artificially sweetened breath mints. Could the artificial sweeteners and fruit be responsible for part of the constipation and bloating? Is stevia an acceptable artificial sweetener?

If you still have bowel problems on a Nutritarian diet, then you should be more vigilant avoiding the entire FODMAPS load. Beano is not the answer. The goal is to reduce the FODMAP load significantly, depriving the bacteria of a food source, which will reduce methane production. You should also avoid all polyols- these artificial sweeteners are another source of the problem. Both the fruit and the sweeteners are likely responsible for bloating and constipation. You should avoid all high fructose fruits. You can use stevia occasionally, but not every day.

Remember, for you it is the FODMAP load that is important. Most people can do well giving up the list discussed during the webinar. You should chew each bite very well, making sure you maximize the release of important phytochemicals like ITCs from your greens. You should also add the probiotic. If you continue to have symptoms after a period of a few months, we can reassess.