Starving your gut for 5 days a month could heal Crohn’s disease. A groundbreaking Stanford Medicine trial proves a calorie-restricted “fasting mimicking diet” dramatically cuts inflammation and symptoms in mild-to-moderate Crohn’s patients, better than standard care alone. Published in Nature Medicine, this first-of-its-kind national study gives doctors concrete dietary advice they’ve long struggled to provide.
Affecting 1 million Americans, Crohn’s causes debilitating gut inflammation, diarrhea, cramps, pain, and weight loss. Steroids work but cause serious side effects. Patients desperately ask, “What should I eat?”—yet no large trials existed. This study tested if extreme calorie cuts could calm the overactive immune system driving Crohn’s.
Researchers enrolled 97 patients nationwide in a randomized controlled trial. 65 followed the fasting mimicking diet (FMD): 5 days/month eating just 700-1,100 plant-based calories, then normal eating for 25 days. 32 controls ate normally while continuing standard medications. All tracked symptoms and provided stool/blood samples for inflammation markers over 3 months.
Stunning results:
• 67% of FMD group saw major symptom improvement vs. <50% controls
• Fecal calprotectin (gut inflammation marker) dropped significantly in FMD group
• Inflammatory lipids and immune molecules decreased in FMD patients’ blood
• Benefits appeared after just one FMD cycle
• Mild side effects (fatigue, headache) but no serious problems
Extreme calorie restriction reduces inflammatory signals while starving harmful gut bacteria. FMD mimics water fasting benefits without total starvation. Researchers now study microbiome shifts explaining these gains.
FMD offers a safe, drug-free option reducing steroid reliance. Patients alternate normal eating with brief “reset” periods. Future trials test longer use and ulcerative colitis. Doctors finally have data beyond, “Avoid trigger foods.”
Crohn’s patients don’t need endless pills—5 hungry days monthly might heal their gut. This simple dietary hack could transform inflammatory bowel disease treatment worldwide.
REFERENCE: Kulkarni, C., et al. (2026). A fasting-mimicking diet in patients with mild-to-moderate Crohn’s disease: a randomized controlled trial. Nature Medicine. doi: 10.1038/s41591-025-04173-w. https://www.nature.com/articles/s41591-025-04173-w
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