Can a Calorie-Restricted Diet Help With Crohn’s Disease?

But here’s the core tension: While studies suggest calorie restriction may reduce gut inflammation, many people with Crohn’s disease already struggle to maintain a healthy weight due to malabsorption, reduced appetite, or flare-related complications that make it difficult to eat. For them, eating less isn’t a simple or risk-free strategy.

Cutting caloric intake through fasting or time-restricted eating may actually help the immune system dial down its overactive response, according to Elena Ivanina, DO, a New York City–based gastroenterologist and founder of the Center for Integrative Gut Health.

“The scientific rationale behind calorie restriction or fasting for Crohn’s disease centers on three interconnected mechanisms: activating cellular ‘cleanup,’ or autophagy; reducing inflammatory signaling molecules through cytokines; and resetting immune function — all of which address core drivers of gut inflammation,” Dr. Ivanina says.

In a nutshell:

• Autophagy is the body’s natural cleaning-out process that’s triggered when your cells are deprived of nutrients, such as during periods of fasting. It’s already being studied for its role in preventing and fighting disease, including inflammatory conditions.

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   In people with Crohn’s disease, researchers have suggested that defects in autophagy-related genes can impair the gut’s ability to clear harmful bacteria and regulate the immune system, which may fuel chronic inflammation.

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• Cytokines are proteins that function as immune system messengers. In people with Crohn’s disease, certain cytokines signal the body to keep attacking the gut lining, which drives ongoing inflammation.

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   Research suggests that intermittent fasting and other diet restriction strategies can lower pro-inflammatory cytokines and help shift the immune system to a less inflamed state.

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A growing body of research also suggests fasting may influence the gut microbiome, boosting beneficial bacteria that tame inflammation, Ivanina says.

Most of the early enthusiasm around calorie restriction and Crohn’s disease came from animal research. Now human studies are beginning to test whether those findings translate to patients, Ivanina says.

Compared with 15 controls, they saw a 40-percent reduction in disease activity and a 50-percent reduction in abdominal discomfort. They also lost an average of 5.5 pounds (lb) and improved inflammatory and metabolic markers. Because participants did not significantly change what or how much they ate, researchers believe meal timing drove the results.

Circadian rhythm may be a key factor in nutrient signaling, hormone release, digestion and even microbiome function, says Maitreyi Raman, MD, the study’s senior author and an associate professor of medicine at the University of Calgary.

“We hypothesize eating in a specific window when these physiological processes are most coordinated contributed to these positive results,” Dr. Raman says. She noted that fasting periods may improve fat utilization and cut visceral fat, which is a known contributor to systemic inflammation.

Despite these optimistic findings, calorie-restricted diets and intermittent fasting aren’t for everyone.

Nutrient density is a priority for those Crohn’s patients, for whom every calorie counts. Restricting may worsen existing nutritional gaps, says Chelsea Cross, RD, a registered dietitian and personal trainer who has Crohn’s disease and works with clients with IBD. “Already nutrients are not being optimally absorbed, so a calorie-restricted diet would just further decrease potential [for nutrients] to be taken in,” she says.

Weight loss, muscle loss, and vitamin deficiencies are the biggest risks people with Crohn’s may encounter if they try unsupervised calorie restriction diets, Ivanina says.

Nutritional deficiency risk depends on what part of the bowel Crohn’s affects. But, in general, Crohn’s patients are at higher risk for deficiencies in vitamin B12, iron, and fat-soluble vitamins (vitamin A, D, E, K), as well as muscle loss, she says.

Ivanina says certain other people with Crohn’s disease should also steer clear of fasting and calorie-restricted diets, including those with:

• Active malnutrition
• Unexpected weight loss
• More severe or escalating clinical situations, such as recent hospitalization or systemic steroid use
• A history of eating disorders or disordered eating patterns

People with Crohn’s disease who are overweight or living with obesity and have disease that’s well controlled are the best candidates for this type of diet (paired with an anti-inflammatory eating pattern), Raman says.

If you decide to try calorie restriction, make sure you discuss it with your care team, including a gastroenterologist and a dietitian specializing in IBD, who can evaluate you clinically before and during the diet, Ivanina says.

“The red flags to watch out for are weight loss, fatigue, and worsening of IBD symptoms as well as any new symptom that develops that can reflect an underlying nutritional deficiency,” she says.

• Researchers are studying the idea that when you eat and how much you eat may influence immune activity, inflammation, and the gut microbiome — all key factors in Crohn’s disease.
• Small randomized controlled trials suggest strategies like calorie-restriction diets, time-restricted eating, and fasting-mimicking diets may improve Crohn’s symptoms, inflammatory markers, and even body weight and visceral fat in some people with Crohn’s. But larger studies are needed.
• Crohn’s disease can put you at risk for malnutrition, so these eating plans should only be considered after consultation with your healthcare team, including your gastroenterologist and a registered dietitian.