Randomized Mediterranean diet intervention to reverse metabolic syndrome: Preliminary findings at 6-month follow-up

Mariana Calzada; Loni Berkowitz; Barbara Samith; Victoria Pinto; Ximena Martínez; Daniela Sara; Javiera Romero; Camila Mateo; María Verónica Julio; María Soledad Anfossi; María Victoria Binder; Florencia Gutiérrez; María Emilia Riquelme; Margarita Cuevas; Rosario Willatt; Aracelli Keilendt; Patricia Butrón; Alessandra Jarufe; Valentina Leiva; Cristian Salazar; Julio Pulido; Sofía Martin; Francisca Guajardo; Francisca Ojeda; Valentina Alfaro; Andrea von Schultzendorff; Matilde Olivos; Nuria Pedrals; Marcela Bitran; Ivette Ávalos; Josefina Pacheco; Guadalupe Echeverría; Chiara Ruini; Carol Ryff; Druso Pérez; Attilio Rigotti

doi:10.1016/j.clnesp.2026.103110

Randomized Mediterranean diet intervention to reverse metabolic syndrome: Preliminary findings at 6-month follow-up

Clin Nutr ESPEN. 2026 Mar 10:73:103110. doi: 10.1016/j.clnesp.2026.103110. Online ahead of print.

Authors

Mariana Calzada¹, Loni Berkowitz², Barbara Samith¹, Victoria Pinto³, Ximena Martínez⁴, Daniela Sara⁴, Javiera Romero⁴, Camila Mateo⁴, María Verónica Julio⁴, María Soledad Anfossi⁴, María Victoria Binder⁴, Florencia Gutiérrez⁴, María Emilia Riquelme⁴, Margarita Cuevas⁴, Rosario Willatt⁴, Aracelli Keilendt⁴, Patricia Butrón⁴, Alessandra Jarufe⁴, Valentina Leiva⁴, Cristian Salazar⁴, Julio Pulido⁴, Sofía Martin⁴, Francisca Guajardo⁴, Francisca Ojeda⁴, Valentina Alfaro⁴, Andrea von Schultzendorff¹, Matilde Olivos⁴, Nuria Pedrals², Marcela Bitran⁴, Ivette Ávalos⁵, Josefina Pacheco⁴, Guadalupe Echeverría², Chiara Ruini⁶, Carol Ryff⁷, Druso Pérez⁴, Attilio Rigotti⁸

Affiliations

¹ Departamento de Nutrición, Diabetes y Metabolismo, Escuela de Medicina, Pontificia Universidad Católica, Santiago, Chile.
² Departamento de Nutrición, Diabetes y Metabolismo, Escuela de Medicina, Pontificia Universidad Católica, Santiago, Chile; Centro de Nutrición Molecular y Enfermedades Crónicas, Escuela de Medicina, Pontificia Universidad Católica, Santiago, Chile.
³ Departamento de Nutrición y Dietética, Escuela de Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica, Santiago, Chile.
⁴ Centro de Nutrición Molecular y Enfermedades Crónicas, Escuela de Medicina, Pontificia Universidad Católica, Santiago, Chile.
⁵ Clínica Bupa Santiago, Santiago, Chile.
⁶ Department for Life Quality Studies, University of Bologna, Rimini, Italy.
⁷ Institute on Aging and Department of Psychology, University of Wisconsin-Madison, Madison, WI, USA.
⁸ Departamento de Nutrición, Diabetes y Metabolismo, Escuela de Medicina, Pontificia Universidad Católica, Santiago, Chile; Centro de Nutrición Molecular y Enfermedades Crónicas, Escuela de Medicina, Pontificia Universidad Católica, Santiago, Chile. Electronic address: arigotti@uc.cl.

PMID: 41819423
DOI: 10.1016/j.clnesp.2026.103110

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.

Keywords: CHILEMED trial; Cardiometabolic health; Clinical nutrition; Dietary counseling; Public health nutrition.