Differential Glycemic Effects of Low-versus High-Glycemic Index Mediterranean-Style Eating Patterns in Adults at Risk for Type 2 Diabetes: The MEDGI-Carb Randomized Controlled Trial
Journal article, 2022

A Mediterranean-style healthy eating pattern (MED-HEP) supports metabolic health, but the utility of including low-glycemic index (GI) foods to minimize postprandial glucose excursions remain unclear. Therefore, we investigated the relative contribution of GI towards improvements in postprandial glycemia and glycemic variability after adopting a MED-HEP. We conducted a randomized, controlled dietary intervention, comparing high-versus low-GI diets in a multi-national (Italy, Sweden, and the United States) sample of adults at risk for type 2 diabetes. For 12 weeks, participants consumed either a low-GI or high-GI MED-HEP. We assessed postprandial plasma glucose and insulin responses to high-or low-GI meals, and daily glycemic variability via continuous glucose monitoring at baseline and post-intervention. One hundred sixty adults (86 females, 74 males; aged 55 ± 11 y, BMI 31 ± 3 kg/m2, mean ± SD) with ≥two metabolic syndrome traits completed the intervention. Postprandial insulin concentrations were greater after the high-GI versus the low-GI test meals at baseline (p = 0.004), but not post-intervention (p = 0.17). Postprandial glucose after the high-GI test meal increased post-intervention, being significantly higher than that after the low-GI test meal (35%, p < 0.001). Average daily glucose concentrations decreased in both groups post-intervention. Indices of 24-h glycemic variability were reduced in the low-GI group as compared to baseline and the high-GI intervention group. These findings suggest that low-GI foods may be an important feature within a MED-HEP.

Metabolic syndrome


Impaired glycemic control

Metabolic health

Continuous glucose monitoring

Meal glucose tolerance test

Oral glucose tolerance test

Glycemic variability

Metabolic risk factors

Mediterranean diet


Robert E. Bergia

College of Health and Human Sciences

Rosalba Giacco

University of Naples Federico II

Istituto di Scienze dell'Alimentazione

Thérése Hjorth

Chalmers, Biology and Biological Engineering, Food and Nutrition Science

Izabela Biskup

Chalmers, Biology and Biological Engineering, Food and Nutrition Science

Wenbin Zhu

Purdue University

Giuseppina Costabile

University of Naples Federico II

Marilena Vitale

University of Naples Federico II

Wayne W. Campbell

College of Health and Human Sciences

Rikard Landberg

Chalmers, Biology and Biological Engineering, Food and Nutrition Science

Gabriele Riccardi

University of Naples Federico II


2072-6643 (ISSN) 20726643 (eISSN)

Vol. 14 3 706

Subject Categories

Endocrinology and Diabetes

Food Science

Nutrition and Dietetics

Areas of Advance

Health Engineering



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