If, like 80% of the 10% of people suffering from IBS (1), identified food to be a trigger of your symptoms (2), you may then wonder if stop eating could help.
Of course, not eating at all is not sustainable, but fasting for 14 or 16h per day and eat only on a 10-8h window is possible.
Intermittent fasting may work, but it efficiency will depend on the type of IBS as well as the cause of IBS and your lifestyle.
To understand, let me briefly talk to you about the Migrating Motor Complex (MMC).
The MMC is like the broom in our gut. Approximately 90 min after the end of the meal/snack, he starts working by waves in order to “clean” the leftover food left behind and the bacteria (which won’t thrive if there is no food left for them anyway).
Whereas there is still little evidence supporting the MMC’s role in IBS, one study showed the MMC of IBS patients are changed. The small intestinal motility dysfunction could then be one of the pathogenic factors of IBS (3). Also, MCC role has been proven in SIBO (4).
Fasting can help promote the MMC mechanism, and thus, could improve the GI motility and the relief of trapped gas and constipation.
Intermittent fasting is not a weight-loss diet. Consequently, a food intake is not in theory reduced, but consumed in a time-restricted period.
This means that meals might be bigger, which could lead to abdominal pain, acid reflux or nausea.
Additionally, if you are sensitive to FODMAPs, you are at higher risk to accumulate some of the FODMAPs (even if you are still consuming low FODMAPs foods), which could lead to IBS-like symptoms (bloating, pain, abdominal cramps…).
If you followed or are following a low FODMAP diet, you may already have a difficult time managing the diet with your daily and social life. Adding another restriction might be too much if you are not reading for it. As mental health plays a huge role in IBS, avoid changing to many things in the same time.
Finally, even if fasting show some benefits, we do not know yet the long-time effects of fasting on our gut health. Does intermittent fasting could have a negative impact on our gut bacteria?
While intermittent fasting might work for some, scientific evidence is still minimal (only one study involving 58 participants with moderate to severe IBS) (5).
NICE Guidelines do not support intermittent fasting as a way of managing IBS.
The best way is to ask yourself if intermittent fasting could work for you and could fit in your lifestyle and to discuss it with your doctor or your registered dietitian.
Algera J, Colomier E, Simrén M. The dietary management of patients with irritable bowel syndrome: a narrative review of the existing and emerging evidence. Nutrients. 2019;11(9):2162.
Schnedl WJ, Enko D. Histamine Intolerance Originates in the Gut. Nutrients. 2021;13(4):1262.
Wang S-H, Dong L, Luo J-Y, Li L, Zhu Y-L, Wang X-Q, et al. A research of migrating motor complex in patients with irritable bowel syndrome. Zhonghua nei ke za zhi. 2009;48(2):106-10.
Pimentel M, Soffer EE, Chow EJ, Kong Y, Lin HC. Lower frequency of MMC is found in IBS subjects with abnormal lactulose breath test, suggesting bacterial overgrowth. Digestive diseases and sciences. 2002;47(12):2639-43.
Kanazawa M, Fukudo S. Effects of fasting therapy on irritable bowel syndrome. International journal of behavioral medicine. 2006;13(3):214-20.