I observe my religious fasting days and last year when I was fasting for a few days, I noticed a significant improvement in my symptoms. Does fasting affect the symptoms of IBS?
Dr. Farhadi: The studies on this subject are very limited. There is a relatively good study from Japan in which they used a 10 days fasting therapy (starvation with permission to drink water only) followed by five days of feeding and observed the symptoms after this intervention [Kanazawa M] . Researchers observed a significant improvement in symptoms of IBS in their study compared to control subjects with IBS who received conventional therapies. The findings of this study make sense because symptoms of the IBS is usually related to food intake or bowel movement and if you are fast for 10 days you will not have any stimuli to cause symptoms. Whether the benefits observed after a short period of fasting therapy would extend beyond the study period needs to be determined. Based on this study result you may think it is safe and helpful for your IBS to have a fasting period. However, it is hard to extrapolate the information from this study to religious fasting practice for several reasons: 1) this study showed the beneficial effect of very long fasting period and not a short one that is common in religious fasting practice that is usually 14-24 hours; and 2) in religious fasting practice, the observant usually eats a large meal (not at the typical mealtime) after fasting hours. Thus, I would not be surprised if the fasting practice provides some relief of symptoms during fasting hours. I would also not be surprised if this relief is followed by an exacerbation of symptoms after heavy meal followed the end of the fasting hours. Overall, I think the response of each individual to the fasting period can be quiet different. Some individuals may experience more benefit from the fasting period while some may have an exaggeration of symptoms. Regardless of symptoms, there is no organic damage to the gastrointestinal tract in subjects with IBS with fasting. Based on these explanations, my suggestion is to use your own experience and see whether you are in the group that their IBS symptoms alleviate or exacerbate during this religious practice and make the call.