Summary:
This study is a randomized controlled trial which examined whether a fasting-mimicking diet (FMD), which is a short, structured, low-calorie diet designed to produce the biological effects of fasting while still allowing some food intake, could improve outcomes in adults with mild-to-moderate Crohn’s disease. Participants in the intervention group followed a five-day FMD each month for three months and returned to their usual diet between cycles, while the control group continued their regular diet throughout. The findings showed that the FMD group had better clinical outcomes than the control group. A meaningful reduction in disease activity was achieved in 69.2% of participants in the FMD group compared with 43.8% in the control group. Clinical remission was also more common in the FMD group (64.6%) than in the control group (37.5%). In addition, a marker of intestinal inflammation decreased in the FMD group but increased in the control group. Further exploratory analyses indicated that the FMD was associated with reductions in inflammatory lipid markers and immune-related gene activity, which aligned with the observed improvements in disease activity. Overall, this study demonstrates that periodic use of an FMD leads to improved outcomes compared to a usual diet in people with mild-to-moderate Crohn’s disease, supporting its potential role as an additional therapy for inflammatory conditions.
Abstract:
In healthy individuals, short cycles of a fasting-mimicking diet (FMD) decrease systemic inflammatory markers and improve metabolic health. Potential benefits of FMD have not been investigated in Crohn’s disease (CD). We conducted an open-label, randomized, controlled trial to assess the effects of FMD in adults with mild-to-moderate CD. Patients in the FMD group followed an FMD for five consecutive days per month for three consecutive months, returning to their regular baseline diet on non-FMD days. Control participants continued their baseline diet. The primary outcome of clinical response was a reduction in CD Activity Index (CDAI) of at least 70 points or CDAI of ≤150 after the third 5-day diet cycle. Forty-five patients in the FMD group (69.2%) and 14 patients in the control group (43.8%) met the primary outcome of clinical response (P = 0.03). Forty-two patients in the FMD group (64.6%) and 12 patients in the control group (37.5%) achieved the secondary outcome of clinical remission (P = 0.02). There was also a decline from baseline in fecal calprotectin (an inflammatory marker) in the FMD group compared with the control group (−22.0% versus 8.0%, P = 0.03). Exploratory analyses of plasma metabolites and peripheral blood mononuclear cell gene expression revealed post-FMD decreases in key inflammatory lipid mediators and immune-effector transcripts, concordant with reduced CD activity. Together, these findings demonstrate that FMD is superior to a baseline diet for inducing clinical response, clinical remission and biochemical improvement in mild-to-moderate CD, and support further investigation of FMD as an adjunctive therapy for chronic inflammatory diseases. ClinicalTrials.gov registration: NCT04147585.
Article Publication Date: 13/01/2026
DOI: 10.1038/s41591-025-04173-w
