Researchers tested whether a special eating pattern called a fasting-mimicking diet could help people with Crohn’s disease—a condition that causes inflammation in the digestive system. For three months, some patients ate very little food for five days each month, then ate normally the rest of the time. Compared to people who ate their regular diet, those who tried this eating pattern had better symptom control and less inflammation in their bodies. The results suggest this approach might be a helpful addition to regular Crohn’s disease treatment, though more research is needed to confirm these findings.

The Quick Take

  • What they studied: Whether eating very little food for five days each month could reduce inflammation and improve symptoms in people with mild-to-moderate Crohn’s disease
  • Who participated: Adults with mild-to-moderate Crohn’s disease. The study included 65 people in the fasting group and 45 in the regular diet group (110 total participants)
  • Key finding: About 69% of people who tried the fasting-mimicking diet had significant improvement in their Crohn’s symptoms, compared to only 44% of people who ate their regular diet. Additionally, 65% of the fasting group went into remission (symptom-free), versus 38% in the regular diet group
  • What it means for you: If you have mild-to-moderate Crohn’s disease, this eating pattern may help reduce your symptoms and inflammation. However, this is one study, and you should always talk to your doctor before trying any new diet, especially with a condition like Crohn’s disease

The Research Details

This was a randomized controlled trial, which is considered one of the strongest types of medical research. Researchers randomly assigned people with Crohn’s disease into two groups: one group followed a fasting-mimicking diet (eating very little for five days each month for three months), while the other group continued eating their normal diet. The fasting-mimicking diet wasn’t complete starvation—participants ate specially designed foods that were very low in calories but contained important nutrients.

Researchers measured how well the diet worked by tracking the CD Activity Index (CDAI), which is a standard scoring system doctors use to measure Crohn’s disease severity. They also measured inflammation markers in blood and stool samples to see if the diet reduced inflammation in the body.

The study was ‘open-label,’ meaning both the patients and researchers knew who was in which group. This is important to note because sometimes knowing which treatment you’re getting can affect results.

This research approach is important because Crohn’s disease is a serious condition that causes ongoing inflammation in the digestive system, and current treatments don’t work well for everyone. By testing a fasting-mimicking diet in a controlled way, researchers could see if this approach actually helps reduce inflammation and symptoms, rather than just guessing. The use of blood and stool markers to measure inflammation gives objective evidence beyond just asking patients how they feel.

This study was published in Nature Medicine, a highly respected scientific journal, which suggests the research met rigorous quality standards. The study used a control group (people eating normally) for comparison, which strengthens the findings. However, the study was relatively small with 110 participants total, and it was open-label, meaning both patients and doctors knew who was in each group. Larger studies with more participants would provide even stronger evidence.

What the Results Show

The main finding was that the fasting-mimicking diet worked better than a regular diet for improving Crohn’s disease. About 69% of people in the fasting group (45 out of 65 people) had significant improvement in their symptoms—defined as either a major reduction in their disease activity score or reaching very low disease activity levels. In comparison, only 44% of people in the regular diet group (14 out of 45 people) had similar improvement.

For clinical remission (meaning symptoms essentially disappeared), 65% of the fasting group achieved this compared to 38% of the regular diet group. This is a meaningful difference that suggests the fasting-mimicking diet helped more people feel better.

Researchers also measured inflammation markers in stool samples (called fecal calprotectin), which is a reliable way to measure gut inflammation. The fasting group showed a 22% decrease in this marker, while the regular diet group actually had an 8% increase. This suggests the fasting-mimicking diet reduced inflammation in the digestive system.

Additionally, researchers examined blood samples and found that the fasting-mimicking diet reduced inflammatory molecules and changed immune system activity in ways that would be expected to reduce inflammation.

Beyond the main results, researchers looked at blood samples to understand how the fasting-mimicking diet worked. They found that certain inflammatory lipid mediators (fat-based molecules that cause inflammation) decreased after the fasting periods. They also found changes in immune cell gene expression, meaning the immune system was functioning differently in ways that reduce inflammation. These findings help explain why the diet appeared to work—it wasn’t just coincidence, but actual changes in the body’s inflammatory processes.

Previous research in healthy people showed that fasting-mimicking diets could reduce inflammation and improve metabolic health. This study is important because it’s the first to test whether these benefits also apply to people with Crohn’s disease, a serious inflammatory condition. The results suggest that what works in healthy people may also help people with inflammatory bowel diseases, opening new possibilities for treatment.

Several limitations should be considered. First, the study was relatively small with only 110 participants—larger studies would provide stronger evidence. Second, the study was open-label, meaning both patients and doctors knew who was in each group, which could influence how people reported their symptoms. Third, the study only lasted three months, so we don’t know if benefits continue longer or if people can stick with this diet long-term. Fourth, the study only included people with mild-to-moderate Crohn’s disease, so results may not apply to people with severe disease. Finally, this was a single study, and more research is needed to confirm these findings.

The Bottom Line

Based on this research, the fasting-mimicking diet appears promising for people with mild-to-moderate Crohn’s disease (moderate confidence level). However, this is one study, and more research is needed. If you have Crohn’s disease and are interested in trying this approach, discuss it with your gastroenterologist first. Never start any new diet without medical supervision, especially with a condition like Crohn’s disease. This should be considered as a potential addition to, not replacement for, standard medical treatment.

This research is most relevant to people with mild-to-moderate Crohn’s disease who are looking for additional ways to manage their symptoms. It may be less relevant for people with severe Crohn’s disease or other inflammatory bowel conditions (though it might still be worth discussing with a doctor). People without Crohn’s disease shouldn’t assume this diet would help them, as the study specifically tested it in people with this condition.

In this study, people followed the fasting-mimicking diet for three months (five days per month for three months). Most improvements were measured after this three-month period. Realistically, if you were to try this approach, you should expect to give it at least three months before evaluating whether it’s helping. Some people might see improvements sooner, while others might need the full three months.

Want to Apply This Research?

  • Track your Crohn’s disease symptoms daily using a simple scale (1-10 for pain, bloating, and bowel movement frequency). Record which days you’re doing the fasting-mimicking diet and compare symptom patterns before, during, and after fasting periods. Also note energy levels and any side effects.
  • If trying this approach with doctor approval, use the app to set reminders for your five-day fasting-mimicking diet cycles each month. Create a meal plan feature to help you prepare approved foods for fasting days. Set goals for symptom reduction and track progress toward clinical remission.
  • Use the app to create a monthly calendar showing fasting days and regular eating days. Track inflammation-related symptoms (abdominal pain, diarrhea, urgency) separately from other symptoms. Compare monthly summaries to see if symptoms improve over the three-month trial period. Share this data with your doctor to help evaluate whether the diet is working for you.

This research is promising but represents a single study. The fasting-mimicking diet should never be started without explicit approval and supervision from your gastroenterologist or healthcare provider. This approach is not a replacement for standard Crohn’s disease medications and treatments. People with severe Crohn’s disease, those who are pregnant or breastfeeding, or those with a history of eating disorders should not attempt this diet without extensive medical supervision. Always consult your healthcare team before making significant dietary changes, especially with a chronic inflammatory condition.