Mediterranean diet triples metabolic syndrome reversal rate vs low-fat diet in interim trial

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Clinical nutrition ESPEN Published June 1, 2026 Medically reviewed June 1, 2026 Study authors: Calzada Mariana, Berkowitz Loni, Samith Barbara, Pinto Victoria, Martínez Ximena, Sara Daniela, Rome… PubMed ↗ DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Consider Mediterranean diet as a first-line dietary strategy for metabolic syndrome reversal, but await final 12-month trial results.

This interim analysis of a 12-month randomized controlled trial enrolled 246 middle-aged men and women with metabolic syndrome in Chile. Participants were assigned to a Mediterranean diet (MedDiet) with or without psychological well-being support or a low-fat diet. At the 6-month interim analysis (156 completers), the primary outcome of metabolic syndrome reversal occurred in 36% of the MedDiet group vs 11% of the low-fat diet group (adjusted hazard ratio 3.84, p<0.01). Secondary outcomes including dietary adherence, waist circumference, triglycerides, and glucose levels all favored the MedDiet, though effect sizes and absolute numbers were not reported. Safety and tolerability data were not reported. Limitations include the interim nature of the analysis and that only 156 of 246 participants completed the 6-month follow-up. While the findings suggest a substantial benefit of MedDiet for metabolic syndrome reversal, clinicians should interpret with caution until the full 12-month results are available. The study supports promoting MedDiet adherence for chronic disease management in Chile.

Study Details

Study typeRct

Sample sizen = 246

EvidenceLevel 2

Follow-up12.0 mo

PublishedJun 2026

PMID41819423

View Original Abstract ↓

BACKGROUND: Metabolic syndrome (MetS) is a significant public health issue in Chile, affecting approximately 40 % of the adult population and increasing the risk of chronic diseases. Although evidence from Mediterranean countries has shown benefits of the Mediterranean diet (MedDiet) improving metabolic parameters and reversing MetS, its impact in non-Mediterranean populations remains unclear. AIM: The CHILEan MEDiterranean (CHILEMED) study is evaluating MetS reversal effectiveness of a MedDiet, with or without well-being support, compared to a low-fat diet. METHODOLOGY: CHILEMED is an ongoing 1-year, parallel-group randomized controlled trial, and this report presents an interim analysis with preliminary findings at 6 months of follow-up. A total of 246 participants (men and women, middle-aged, with comparable baseline cardiometabolic risk profiles) diagnosed with MetS have been assigned to low-fat diet (control), MedDiet, or MedDiet with psychological well-being interventions. Participants received face-to-face and online nutritional counseling specific to their assigned dietary intervention. Clinical assessments, including anthropometry, biochemical parameters, and dietary adherence, were performed at baseline and 6 months. The primary outcome was MetS reversal, while secondary outcomes included changes in dietary adherence and MetS components. RESULTS: Preliminary analyses of 156 participants completing the 6-month follow-up showed a significantly greater increase in MedDiet adherence in the combined MedDiet (with and without psychological well-being intervention) groups compared with the low-fat diet group. Participants in the MedDiet group exhibited greater reduction in waist circumference, triglycerides, and glucose levels compared to the low-fat diet group. Notably, 36 % of individuals in the MedDiet intervention experienced MetS reversal, compared to only 11 % in the low-fat diet group (p < 0.01), with an adjusted hazard ratio of 3.84 for MetS reversal in the MedDiet versus the control group. CONCLUSIONS: These preliminary 6-month results from the ongoing 1-year randomized CHILEMED trial provides evidence supporting MedDiet's effectiveness in improving metabolic health and reversing MetS in Chilean adults. Given changing dietary patterns and rising prevalence of MetS-related conditions, promoting adherence to MedDiet may be a key strategy for chronic disease management and public health policies in Chile.