A randomized controlled trial funded by the Crohn’s & Colitis Foundation found that time-restricted eating, a form of intermittent fasting, significantly reduced disease activity and systemic inflammation in adults with Crohn’s disease who were also overweight or obese. This type of diet has been studied primarily in metabolic and inflammatory diseases. Studies show that it can improve obesity, visceral fat, blood sugar and insulin resistance and reduce cardiovascular risk factors. It also reduces systemic inflammatory markers, which is particularly relevant for chronic inflammatory diseases such as Crohn’s disease. The study, conducted by researchers at the University of Calgary, is the first to demonstrate that restricting meals to an 8-hour daily window can reduce Crohn’s disease activity by 40% and abdominal discomfort by 50% over 12 weeks compared to a typical eating pattern.
Participants who adhered to the intermittent fasting schedule lost an average of about 5.5 pounds during the study, while those in the control group gained about 3,7 pounds. Blood tests also showed significant improvements in markers associated with inflammation and immune function, including reduced leptin and PAI-1 levels. These changes occurred without any calorie restriction instructions. The results were published in the journal “Gastroenterology”. People with IBD are advised to consult their doctor before changing their eating habits to determine whether intermittent fasting is suitable for them.
Crohn’s Disease and Diet
Crohn’s disease is a chronic inflammatory bowel disease in which the immune system mistakenly attacks its own intestinal wall, causing persistent inflammation that can affect the entire digestive tract from the mouth to the anus, but most frequently the transition from the small to the large intestine. The exact cause is not fully understood, but is thought to be a combination of genetic predisposition, dysregulation of the immune system, changes in the intestinal flora and environmental factors such as smoking. Typical symptoms include recurring abdominal pain, chronic diarrhea (sometimes with blood), weight loss, fatigue and fever; symptoms outside the intestines such as joint inflammation, skin changes or eye inflammation can also occur. In the long term, the disease can lead to complications such as intestinal narrowing (stenosis), fistulas, malnutrition and a reduced quality of life, which is why early diagnosis and ongoing medical care are important.
Studies on nutrition in Crohn’s disease show that although nutrition is not a “cure” in the classic sense, it can influence the inflammatory process, symptom burden and remission – depending on the type of diet, phase of the disease and individual differences.
One well-documented approach is exclusive enteral nutrition (EEN), where patients are fed exclusively on a liquid, nutrient-defined drinking diet without solid food for weeks. This therapy shows a high remission rate and positive effects on the intestinal microbiome and inflammatory markers in many patients – especially children and adolescents – which is why it is particularly recommended for acute relapses. Observational and cross-sectional studies also suggest that generally “lower inflammation” dietary patterns – e.g. rich in fresh fruit and vegetables, complex carbohydrates, omega-3 fatty acids and low in highly processed foods, sugar and refined fats – are associated with lower levels of inflammation in the gut and may promote longer symptom-free periods.
How Time-Restricted Eating Works
Time-restricted eating (TRF) means eating all meals within a set period of 8 hours per day and fasting for the remaining 16 hours. The aim is to give the body longer breaks between meals, which can stabilize blood sugar levels, improve insulin sensitivity and promote fat burning; this diet is also based on the natural day-night rhythm (circadian rhythm), which can have a positive effect on metabolism and digestion. However, the quality and quantity of food in the eating window is still crucial, as this diet does not prescribe a specific diet, but only regulates the timing of food intake.
“This study shows that while weight loss is an important outcome in people with obesity and Crohn’s disease, time-restricted diets offer additional benefits beyond just weight loss,” said Dr. Maitreyi Raman, Associate Professor of Medicine at the University of Calgary and lead author of the study. “We saw significant improvements in disease symptoms, reductions in abdominal discomfort, favorable changes in metabolism and inflammation, and promising changes in gut bacteria – all suggesting that intermittent fasting can help patients maintain lasting remission from Crohn’s disease.”
Practical Tools to Support those Affected
The research was funded by the Litwin IBD Pioneers program of the Crohn’s & Colitis Foundation. “Time-restricted eating is a promising new approach to help people with Crohn’s disease not only manage their symptoms, but also their overall health,” said Dr. Andres Lorenzo Hurtado, Senior Vice President of Translational Research & IBD Ventures at the Crohn’s & Colitis Foundation. “This research suggests that changing our eating habits – not just our diet – can improve metabolism, boost the immune system and support long-term remission from Crohn’s disease. We are pleased to support studies like this that put patients at the center of new solutions, and encourage further research so that all people with IBD can reap these benefits.”
According to Natasha Haskey, PhD, RD, research associate at the University of British Columbia and lead researcher on the study, people with Crohn’s disease often look for practical tools to support their health in addition to medication. She noted that her research would suggest that time-restricted eating may be a sustainable option that is biologically based and offers patients more options to manage their own well-being.
Reduced Visceral Fat and Less Inflammation in the Gut
Beyond symptom relief, participants in the intermittent fasting group experienced a significant reduction in harmful visceral fat and key inflammatory signals in the bloodstream. Since both groups ate similar amounts of similar foods, the improvements were not simply the result of better diet quality or lower calorie intake. Instead, the results suggest that the timing of meals itself may play an important role in digestive and immune health, as the altered eating rhythm may have a direct effect on inflammatory processes.
As visceral fat produces inflammation-promoting messenger substances, reducing it could be particularly important for Crohn’s patients. At the same time, longer breaks between meals could give the gut time to regenerate and reduce immunological stimuli. Nevertheless, it is important to emphasize that Crohn’s disease is very individual and dietary changes – especially fasting – should always be supervised by a doctor, as not every patient reacts in the same way and being underweight or lacking nutrients can pose a risk.
Although the results are encouraging, the researchers emphasize that larger studies are needed to determine the long-term safety and effectiveness of time-restricted food intake for a broader population of people with IBD.