For many people with Crohn’s disease, diet is often the first place they start when managing symptoms—particularly in milder cases where long-term medication options are limited. In the United States, the only approved therapies for mild Crohn’s are steroids, which can carry side effects with long-term use.

A five-day-a-month fasting diet improved symptoms in seven out of 10 people with Crohn’s disease and brought some into remission, according to a new Stanford study.

The randomized clinical trial found that a fasting-mimicking diet significantly improved both symptoms and key biological markers in people with mild to moderate Crohn’s disease, compared with continuing their usual diet.

“It’s a different therapeutic ‘shape,’” Dr. Sidhartha R. Sinha, an assistant professor of gastroenterology and hepatology and the senior author of the study, told The Epoch Times.

The approach relies on brief dietary “reset” periods—just five days a month—rather than continuous diets such as the Mediterranean or specific carbohydrate diets, or strategies that involve cutting out broad food groups or relying on tube feeding, which can be difficult to sustain long term or costly to follow.

A Short-term Diet With Immediate Benefits

Researchers at Stanford Medicine randomly assigned adults with mild to moderate Crohn’s disease into two groups. 32 participants maintained their usual diet, while 65 followed a fasting-mimicking diet.

A fasting-mimicking diet is a carefully designed, plant-based eating plan that is very low in calories—700 to 1000—but nutritionally defined. Participants followed the diet for five consecutive days per month, over a three-month period.

The goal was to temporarily shift the body into a fasting-like state that could influence immune activity and inflammation.

By the end of the three-month intervention, roughly seven in 10 people following the fasting-mimicking diet experienced a meaningful improvement in symptoms or entered remission, compared with about four in 10 who stayed on their usual diet.

The relatively high response in the control group likely reflects the fact that most participants were already on medication, Sinha said. Still, many who were not receiving treatment also benefited from the fasting-mimicking diet.

The diet continued to outperform the control group even after researchers raised the bar for what counted as improvement—from a 70-point drop to a 100-point reduction in the Crohn’s Disease Activity Index score, which measures symptoms such as abdominal pain, stool frequency, overall well-being, and certain lab markers to gauge disease activity.

Benefits were also evident after just one five-day cycle, showing that even a single round was associated with measurable metabolic and immune shifts rather than requiring prolonged restriction to take effect.

Reduced Inflammation

The improvements were not limited to symptom reports.

Levels of fecal calprotectin—a stool marker commonly used to assess intestinal inflammation in Crohn’s disease—declined in the fasting-mimicking diet group, with more participants achieving a 50 percent reduction, while levels increased slightly in the control group. Because calprotectin rises when inflammatory immune cells accumulate in the intestinal lining, a meaningful drop suggests calmer intestinal inflammation and improved disease control.

Blood tests also revealed biological shifts associated with reduced inflammation. After fasting-mimicking diet cycles, participants showed lower levels of fat-derived inflammatory molecules that are known to fuel intestinal immune activation. At the same time, levels of lipoxins, compounds involved in resolving inflammation, increased.

Researchers also observed reduced levels of inflammatory immune signals—including TNF and IL-18—targets of biologic drugs used in more severe Crohn’s disease.

How Does the Diet Work?

The mechanism may lie in how the diet affects the immune system.

Crohn’s disease is driven by an overactive immune response, and immune cells are highly energy-dependent, producing more inflammatory signals when nutrients are abundant.

By mimicking fasting, the diet activates autophagy, a cellular repair process that allows damaged gut cells to clear debris, recycle components, and regenerate. This cell cleanup allows damaged gut cells to repair and regenerate, while simultaneously calming inflammatory immune activity.

The diet’s relatively high prebiotic fiber content may also support beneficial gut bacteria that help regulate immune responses.

Who Benefited Most–and for How Long?

Participants in the fasting-mimicking diet group consistently reported greater overall improvement, including higher rates of symptom remission, higher quality-of-life scores, and a stronger subjective sense of remission.

However, when participants were followed for three months after stopping the diet cycles, the benefits did not persist, suggesting that this approach would likely need to be repeated periodically or integrated into an ongoing management plan.

People who were not on medical therapy at baseline were more likely to respond to the fasting-mimicking diet than the controls. The diet appeared more effective for Crohn’s disease affecting the colon than for disease limited to the small intestine, possibly because the colon is more sensitive to dietary triggers.

Important Caveats

While the study suggests potential benefits from a fasting-mimicking diet, it relied on a precise, very low-calorie regimen delivered under structured monitoring, making it unclear how easily it can be replicated outside a clinical trial.

Sinha’s team is working to better understand how to generalize the findings and identify which patients are most likely to benefit.

“At this stage, I would only recommend it with clinician input and if you are, among other things, well nourished, not underweight, not pregnant, and not struggling with food insecurity or an eating disorder,” he said. Even though the study reported no serious adverse events, low-calorie interventions can pose risks for people with Crohn’s disease—especially those with unintentional weight loss, malnutrition, dehydration, or micronutrient deficiencies.

That uncertainty makes individualized care essential.

“The findings highlight that dietary tools are not one-size-fits-all,” Kara Siedman, a registered dietitian and director of partnerships at Resbiotic Nutrition, told The Epoch Times. Whether approaches like fasting-mimicking diets help—or cause problems—depends on a person’s disease type, symptoms, and nutritional status, she said.

Some people with Crohn’s may have normal test results but still experience symptoms such as bloating, abdominal pain, or urgency. In those cases, she said, care should begin by ruling out ongoing inflammation and then focus on symptom-specific strategies—such as targeted fiber intake, texture adjustments, or short-term elimination approaches when appropriate—rather than immediately restricting the diet further.

Both experts emphasized the importance of working closely with a care team or a dietitian before attempting major dietary changes, particularly when symptoms persist or nutrition status is uncertain.