- Crohn’s disease is a long-term autoimmune condition of the digestive system, that affects around a million people in the United States.
- It causes symptoms including abdominal pain, mouth ulcers, diarrhea, fatigue, fever, nausea, vomiting, and weight loss.
- Treatments, such as medication, surgery, nutritional supplements, and dietary changes, cannot cure the condition, but aim to alleviate symptoms.
- Now, a study has found that eating a calorie-restricted diet for a few days each month may significantly improve symptoms in people with mild-to-moderate Crohn’s.
It is a long-term autoimmune condition of the intestines, with symptoms including abdominal pain, diarrhea, fatigue, nausea and vomiting, and weight loss.
Although there is no cure, dietary changes and treatment with medications including 5-aminosalicylates (5-ASA), antibiotics,
A new study has found that following a very low calorie, or fasting-mimicking diet for a few days a month caused significant improvement in both physical symptoms and biological indicators in people with mild-to-moderate Crohn’s disease.
Researchers suggest that their findings, published in
Eamon Laird, PhD — lecturer in human Nutrition at Atlantic Technological University Sligo, and adjunct assistant professor at Trinity College Dublin, both in Ireland — who was not involved in this study, commented on the findings to Medical News Today:
“This is an interesting study with some early concept findings that these fasting-mimicking diets may have significant improvements for patients living with Crohn’s disease. […] However, I would like to see more in-depth trials within specific groups of obesity versus normal weight patients, flare ups and types of [Crohn’s] and the combined lifestyle approach of diet plus physical activity.”
In a trial of healthy volunteers, the fasting-mimicking pattern of 5 consecutive days fasting per month for 3 months was found to have metabolic benefits, and reduce inflammatory markers. Therefore, the researchers hypothesized that it might have similar effects in people with Crohn’s.
For their 3-month study, the researchers enrolled 97 people with mild-to-moderate Crohn’s disease. They divided them randomly into two groups — 65 in the fasting-mimicking group, and 32 controls.
The fasting-mimicking group followed a severely calorie-limited, plant-based diet of 700-1,100 calories a day for 5 consecutive days each month. For the rest of the month, they followed their usual diet. Controls followed their usual diet throughout the study.
The researchers measured participants’ response to the diet using the Crohn’s Disease Activity Index (CDAI), which measures severity of Crohn’s symptoms. A positive outcome was a reduction of at least 70 points or CDAI 150 or less after the third 5-day diet cycle.
Thomas Holland, MD, physician-scientist and assistant professor at the RUSH Institute for Healthy Aging, RUSH University, College of Health Sciences in Chicago, IL, not involved in this research, told us that:
“This study is notable because dietary interventions in Crohn’s disease are notoriously difficult to conduct well, yet the investigators used a randomized controlled design and paired symptom-based outcomes with objective biological markers of inflammation. That combination strengthens confidence that the observed improvements were not simply placebo effects or normal symptom fluctuation.”
At the start of the trial, participants in the fasting-mimicking group had a median CDAI of 196, with 195 in the control group.
By the end of the 3 months, 45 (69.2%) of those in the fasting-mimicking group, and 14 (43.8%) of those in the control group had met the goal of a 70 point reduction or CDAI 150 or less. In the treatment group, 42 (64.6%) achieved clinical remission, compared with 12 (37.5%) in the control group.
People in the fasting-mimicking group also showed a significant reduction (-22%) in fecal calprotectin, a protein found in stool samples that indicates intestinal inflammation, with fecal calprotectin more than halved in over a third of the group. Control participants experienced no reduction.
Holland welcomed these findings, telling MNT that, “from a practical standpoint, the results are compelling because they demonstrate that a brief, structured dietary intervention can lead to measurable improvements in both symptoms and inflammatory activity, an area where clinicians have historically had little evidence to guide patients beyond general advice.”
Laird suggested a number of mechanisms behind the improvements produced by this specific fasting-mimicking diet.
“The calorie restriction can suppress inflammation pathways whilst the increase in fibre and (possibly) differences in other micro and macronutrients could also influence inflammation, symptoms and disease status,” he hypothesized.
Holland explained further:
“The fasting-mimicking diet likely improves Crohn’s symptoms by temporarily shifting the body out of a pro-inflammatory metabolic state. From a biological perspective, short-term calorie restriction can reduce the production of inflammatory signaling molecules, alter immune cell behavior, and decrease markers of gut inflammation such as fecal calprotectin. These changes may give the immune system a chance to ‘stand down’ from its chronically activated state in Crohn’s disease.”
“This type of diet may act like a brief reset for an overworked inflammatory system, reducing the constant immune ‘noise’ in the gut and allow the intestinal tissues some time and opportunity to recover,“ he continued.
“Newer data also suggest that these metabolic shifts may influence the gut microbiome, which plays a key role in immune regulation and intestinal health, which further supports a plausible mechanism for symptom improvement,” added Holland.
“This is an interesting proof of concept. However I would like to see more in depth trials within specific groups of obesity vs normal weight patients, flare ups and types of Crohn’s disease and the combined lifestyle approach of diet plus physical activity.”
– Eamon Laird, PhD
As the fasting-mimicking diet produced such positive results in this small study, the researchers suggest that it could be a promising additional approach to treatment of Crohn’s disease, and that the approach merits further investigation.
Holland agreed, but cautioned that “adherence in this study was very high, which is encouraging but may reflect the short duration of restriction and the provision of pre-prepared meal kits.“
“These factors may not fully translate to real-world settings where access, cost, and support vary widely,” he noted.
He also highlighted how participants’ normal diet might affect their response, outlining that, “if participants were consuming a typical Western diet, high in refined carbohydrates, saturated fats, and ultra-processed foods, then even brief, repeated 5-day dietary shifts could have a meaningful anti-inflammatory or immunomodulatory effect.“
“In that sense, the intervention may function less as a magic bullet and more as a recurring opportunity to interrupt inflammatory dietary patterns and promote metabolic recalibration,” he told us.