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• Posted January 14, 2026

Two-Thirds Of Crohn's Disease Patients Benefit From Fasting Diet, Clinical Trial Shows

Fasting a handful of days each month can significantly improve GI symptoms among people with Crohn’s disease.

The new approach, called “fasting mimicking,” improved symptoms among two-thirds of Crohn’s patients who tried it, researchers reported Jan. 13 in the journal Nature Medicine.

“We were very pleasantly surprised that the majority of patients seemed to benefit from this diet,” senior researcher Dr. Sidhartha Sinha, an assistant professor of gastroenterology and hepatology at Stanford University, said in a news release.

“We noticed that even after just one fasting-mimicking diet cycle, there were clinical benefits,” he added.

Crohn’s disease affects about a million Americans, researchers said in background notes. The inflammatory bowel disease causes symptoms like diarrhea, cramping, abdominal pain and weight loss.

Patients frequently turn to their doctor to ask about foods that might improve their Crohn’s symptoms, but up to now there have been few large studies looking at diets that might help manage the disease, researchers said.

“We have been very limited in what kind of dietary information we can provide patients,” Sinha said.

The fasting-mimicking diet involves severely limiting calories for five days in a row each month, researchers said.

During those fasting days patients consume between 700 and 1,100 calories a day, mainly in plant-based meals, researchers said. For the rest of the month, they eat whatever they like.

For this clinical trial, researchers assigned 65 Crohn’s patients to try fasting mimicking for three consecutive months, and compared their results to 32 patients who ate their normal diet.

By the end, 69% of those fasting experienced an improvement in their Crohn’s symptoms, compared with 44% of those who ate as regular, results showed.

What’s more, 65% of the fasting-mimicking group had their Crohn’s symptoms go into clinical remission, compared with 38% of those eating their regular diet. Remission means symptoms nearly or completely go away.

Researchers said the improvement among those who ate their regular diet was likely due to natural symptom fluctuations that occur in Crohn’s disease, alongside the fact that they kept taking their usual medications.

Sinha said he thought fasting mimicking might help Crohn’s patients because research has shown the diet can reduce levels of C-reactive protein, a common indication of systemic inflammation.

“The effects seen on inflammatory markers made this an appealing diet to study in Crohn’s disease since many patients with this disease also have elevated inflammatory markers,” Sinha said.

Stool samples provided by participants showed that those who fasted had a significant decline in fecal calprotectin, a protein in stool that indicates gut inflammation, researchers said.

The samples also revealed declines in inflammatory chemicals produced by fatty acids and immune cells, researchers said.

Researchers are now exploring whether changes in a patient’s gut microbiome brought on by fasting mimicking might explain some of the improvements.

“There’s still a lot more to be done to understand the biology behind how this and other diets work in patients with Crohn’s disease,” Sinha said.

More information

The Crohn’s and Colitis Foundation has more on Crohn’s disease.

SOURCES: Stanford Medicine, news release, Jan. 13, 2026; Nature Medicine, Jan. 13, 2026