It is probably no coincidence that the natural response to indigestion is to stop eating. Fasting gives the digestive tract a break from processing food and offers the gastrointestinal system a time to rest.
There have been a number of studies examining the effects of water-only fasting on gastrointestinal disorders. In 1989, Scottish researchers compared the effects of fasting with 19 patients whose duodenal ulcers would not heal despite treatment with the drug ranitidine.
During the study, the patients continued to receive ranitidine, which appeared to work significantly better when combined with fasting. The researchers found that on the days when the patients fasted, gastric acidity was significantly less than on the days when food was consumed. The researchers concluded that “Prolonged fasting can improve the control of gastric secretion and may allow resistant ulcers to heal.”
In a random trial of 88 patients with acute pancreatitis, fasting was determined to be more effective than cimetidine, a drug used to treat ulcers. The researchers suggested that “fasting alone be initially used as the simpler and more economical therapy.”
A 2006 Japanese study investigated fasting as a treatment for patients with irritable bowel syndrome (IBS) who had not responded to drug therapy. Of the 58 patients enrolled in this study, 36 underwent fasting, whereas the remaining 22 received drug treatment and psychotherapy. At the start of the study, there were no significant differences in the 4-point severity scales of gastrointestinal and psychological symptoms between the 2 groups.
The fasting protocol for the intervention group consisted of 10 days of fasting followed by 5 days of refeeding. Changes in scores of symptoms before and after each treatment (fasting, drug therapy, and psychotherapy) were analyzed. Fasting therapy significantly improved 7 out of the 10 symptoms assessed; that is, abdominal pain-discomfort (p <.001), abdominal distension (p <.001), diarrhea (p <.001), anorexia (p =.02), nausea (p <.01), anxiety (p <.001), and interference with life in general (p <.001). By comparison, the control therapy significantly improved only 3 out of the 10 symptoms assessed; those being abdominal pain-discomfort (p =.03), abdominal distension (p <.01), and interference with life (p =.01). The researchers concluded that fasting “may have beneficial effects on intractable patients with IBS.”
Other gastrointestinal disorders that respond well to fasting include inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis. Fasting can also help with esophagitis, gastritis, colitis, constipation, and bloating.