A woman sits at a table with a plate of food to her right, and the outline of the same plate of food to her left.

Fasting and IBS: A Helpful or Harmful Strategy?

I've mentioned before that sometimes a little bit of fasting can help me recover from an IBS flare, but it seems fasting can also aggravate my IBS if done too long or not properly.

When is fasting helpful for IBS?

For instance, if I have a bout of diarrhea after dinner, the best thing to do is to not eat or snack on anything else for the rest of the evening and wait until the next morning. I may then also at relatively light the next morning as well until I am feeling much better. Of course, this isn't necessarily really fasting since I don't usually eat anything after dinner anyway for the rest of a given evening. I do find if I am having a bout of diarrhea, that it's best to abstain from eating for at least a few hours and when I do eat, do it very modestly and stick to comparatively "safe" foods. Sometimes the stomach needs a break.

When is fasting harmful for IBS?

However, on the other hand, in general, I find that one of my mainline defenses is sticking to an eating routine. That means I need to eat my main meals around the same time every day and stick to certain staples. And for many others with IBS, adhering strictly to a meal schedule is crucial in managing their condition. And fasting would fly in the face of that.

So, if I am feeling relatively okay, and not in the midst of an active flare, there's really no reason to fast because I will wind up probably hurting myself more than helping my IBS.

Fasting and constipation

Yet, it is true that abstaining from food has helped me not just when I am having diarrhea but constipation. When I first graduated from college and into my very early 20s, I alternated diarrhea with very bad and painful constipation. Desperate to move things along, I would keep eating as well as drinking lots of coffee. But all it did was make me feel more bloated (my belly would become super distended!) with no relief until I finally would bring on a bout of diarrhea and then the cycle would repeat itself.

Finally, I realized I should just stop stuffing myself so much when I was feeling constipated and lay off the food and instead just drink a lot of water (I finally gave up coffee, realizing it was a big part of the problem!). If I did eat, I ate very light so as not to add too much to my already full digestive system. I actually found this seemed to help me a lot better and move things along and I would be able to go to the bathroom normally.

What does research say about fasting and IBS?

I tried to see if there were any scientific studies on fasting for IBS. I found just one, published in 2006 of 84 patients with IBS, 36 of which underwent a fasting regimen. The research revealed that fasting therapy "improved 7 out of the 10 symptoms they assessed" including abdominal pain and discomfort, abdominal distension, diarrhea and interference with life activities. Overall the study concluded that fasting therapy "may have beneficial effects on intractable patients with IBS." 1

Of course, this is just one study with a small pool of participants, so its conclusion should be taken with a grain of salt. As with everything, one should consult a medical professional before trying a new regimen, including fasting. Other medical conditions and individual details should be taken into consideration also before undergoing anything new with diet. For instance, I have very low blood pressure and blood sugar issues. So going more than a half-day without eating would cause me to get very lightheaded and dizzy.

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