Crohn's disease is the result of a chronic inflammation of the intestines and bowel. It affects about one million Americans.

Patients with Crohn's and other inflammatory bowel diseases are often concerned about which foods they should eat and which they should avoid to reduce flare-ups.

A short-term, calorie-restricted diet improved clinical symptoms such as abdominal pain and diarrhea in Crohn's patients.

In a national, randomized clinical trial, a team led by researchers at Stanford University recently found that a short-term, calorie-restricted diet improved clinical symptoms such as abdominal pain and diarrhea in patients with Crohn's disease. Their findings will give physicians something more to recommend to patients to potentially ease their symptoms, according to Sidhartha Sinha, the study's senior author.

The researchers compared the symptoms in participants with mild-to-moderate Crohn's disease who followed either a restricted calorie, fasting-mimicking diet or their regular diet.

Ninety-seven participants from across the U.S. were enrolled in the study: 65 in the fasting-mimicking group and 32 in the control group.

People in the fasting group ate between 700 and 1,100 calories a day for five days each month and were provided with plant-based meals to eat on those fasting days. They ate their regular diet the rest of the month.

At the end of the three-month study period, almost 70 percent of those in the fasting group saw improvement in their symptoms.

“We were pleasantly surprised that most patients seemed to benefit from this diet,” said Sinha. He went on to say the researchers noticed clinical benefits after just one five-day cycle of the fasting-mimicking diet.

Symptoms also improved in 44 percent of those in the control group, which was probably a result of the natural symptom fluctuations in Crohn's disease.

The researchers also looked at changes in biological indicators of inflammation in participants' stool and blood. “Our goal in collecting these and other biospecimens was to dig deeper into why there is this differential response,” Sinha, a professor of gastroenterology and hepatology at the Stanford University School of Medicine, said in a statement.

At the end of the three-month study period, almost 70 percent of those in the fasting group saw improvement in their symptoms.

Compared to the control group, the fasting-mimicking group had a significant decline in levels of a protein in the stool that indicates gut inflammation. Levels of lipid mediators that increase inflammation also declined in the fasting-mimicking group. The immune cells of those in the fasting-mimicking group also produced fewer inflammatory molecules.

“A lot more needs to be done to understand the biology behind how this and other diets work in patients with Crohn's disease,” said Sinha. Going forward, the researchers want to look at how changes in the gut microbiome could explain some of the benefits of a fasting-mimicking diet.

The study is published in Nature Medicine.