Intermittent Fasting and Crohn’s Disease: Benefits and Risks
- Intermittent fasting (IF), also known as time-restricted feeding or time-restricted eating, has become a prominent dietary trend aimed at regulating blood sugar levels and supporting weight loss.
- Intermittent fasting involves limiting food consumption to a specific window of hours each day while fasting for the remaining time, often extending from dinner through a portion of...
- While some evidence suggests potential benefits for certain populations, research involving people with ulcerative colitis and Crohn's disease is currently limited.
Intermittent fasting (IF), also known as time-restricted feeding or time-restricted eating, has become a prominent dietary trend aimed at regulating blood sugar levels and supporting weight loss. However, medical experts caution that the application of this eating pattern for individuals with inflammatory bowel disease (IBD), specifically Crohn’s disease, remains a subject of significant debate due to mixed research results.
Intermittent fasting involves limiting food consumption to a specific window of hours each day while fasting for the remaining time, often extending from dinner through a portion of the following day.
While some evidence suggests potential benefits for certain populations, research involving people with ulcerative colitis and Crohn’s disease is currently limited.
Research Findings in Crohn’s Disease
A randomized, controlled trial focused on 20 individuals in remission from Crohn’s disease who were overweight or had obesity showed promising results. These participants followed a time-restricted feeding pattern for 12 weeks, eating only during an eight-hour window and fasting for 16 hours a day, six days a week.
The group practicing intermittent fasting experienced a significant decrease in body mass index (BMI), a 50 percent decrease in abdominal discomfort, and a 40 percent reduction in the frequency of bowel movements. The study also noted significant reductions in leptin, which serves as a chemical marker of inflammation. A control group of 15 participants did not experience these benefits.
Despite these findings, the study did not find differences between the intermittent fasting group and the control group regarding fecal calprotectin or C-reactive protein levels, both of which are chemicals used to indicate the presence of inflammation.
Commenting on the trial, Bharati Kochar, MD, a gastroenterologist at the Crohn’s and Colitis Center at Massachusetts General Hospital in Boston, stated:
“This was an intriguing and well-done study that, combined with other recent studies, suggests that there may be a role for intermittent fasting, or time-restricted eating, in inflammatory bowel disease,”
Bharati Kochar, MD
Dr. Kochar added that while time-restricted eating has shown anti-inflammatory benefits in mice models, interventions that work in animals do not always translate to humans in IBD cases.
Contradictory Evidence and Limitations
Other research presents a more complicated picture. A review of individuals who were overweight or had obesity but did not have Crohn’s found that intermittent fasting may offer little to no difference in quality of life or weight loss when compared to traditional calorie-restricted dieting.
Studies regarding fasting during Ramadan have also yielded varied results. One study of 100 people with Crohn’s disease in remission during Ramadan reported that 94 percent experienced symptom improvement during daytime fasting hours, though this study lacked a control group for comparison.
Conversely, Bincy Abraham, MD, a gastroenterologist and director of the Fondren Inflammatory Bowel Disease Program at Houston Methodist Hospital’s Underwood Center, noted that another study of IBD patients fasting during Ramadan found that some people with ulcerative colitis experienced worse symptoms, while those with Crohn’s disease saw little change.
Dr. Abraham observed that participants over age 30 and those with higher levels of gut inflammation prior to fasting were more likely to feel worse.
Kelly Kennedy, RDN, of Bousquet Sport in Pittsfield, Massachusetts, noted that while some research suggests time-restricted feeding may improve gut microbiome health and decrease inflammation, “this research is still in its infancy.”
Nutritional Risks and Health Concerns
Experts express concern that intermittent fasting may exacerbate existing nutritional deficiencies common in people with Crohn’s disease. Because IBD affects nutrient absorption, the risk of deficiency exists even for those who are overweight.
Jill Gaidos, MD, a gastroenterologist at Yale New Haven Health and director of clinical research for Yale’s IBD program, highlighted that many Crohn’s patients are deficient in vitamin D. While found in fortified dairy, many patients avoid these products due to lactose intolerance.
Iron deficiency is also prevalent, with approximately 1 in 3 people with IBD suffering from anemia, a condition where the body lacks enough hemoglobin or healthy red blood cells to carry oxygen.
Kennedy warned that restricting eating windows reduces the opportunities to ingest essential minerals, vitamins, and calories, stating:
“Limiting the amount of time you eat each day — or even the number of days per week — also limits the number of opportunities you have to get calories, vitamins, and minerals into your body,”
Kelly Kennedy, RDN
Kennedy further emphasized that intermittent fasting “isn’t a good idea for anyone who is underweight.”
Medical Contraindications and Guidance
Medical professionals advise against intermittent fasting for individuals in several specific circumstances:
- During a disease flare, as it can increase risks of electrolyte imbalances and dehydration.
- For those with strictures or a risk of bowel obstruction.
- For individuals who have undergone major intestinal surgery.
- For those with a history of disordered eating or younger people, as Dr. Abraham noted it may trigger unhealthy relationships with food.
Dr. Abraham suggested that candidates for intermittent fasting should be in remission, have a stable medication regimen, be getting adequate nutrients, and be overweight or obese.
Regardless of candidacy, experts stress that dietary changes are not a substitute for medication and should not be used to treat intestinal inflammation, according to Dr. Gaidos. Instead, she recommends a well-balanced diet low in sugar, processed foods, and indigestible fiber.
Kennedy recommends that any Crohn’s patient considering intermittent fasting work with a registered dietitian-nutritionist specializing in digestive conditions to ensure weight and diet are tracked closely.
Kennedy advised that if the pattern complicates symptoms or leads to a loss of essential vitamins and minerals, the practice should be stopped.