This study aimed to evaluate the association between adherence to the Mediterranean diet and the 20-year incidence of type II diabetes mellitus (T2DM) among adults from the ATTICA study. This study involved a prospective cohort of 3042 men and women recruited at baseline from the Attica region in Greece. Sociodemographic, anthropometric, lifestyle, and clinical characteristics were evaluated at baseline and follow-up examinations; adherence to the Mediterranean diet was assessed through the MedDietScore (range 0–55); four Mediterranean diet trajectories were identified (i.e., increasing, decreasing, and sustained high and sustained low adherence levels). For the present analysis, data from 2000 individuals with complete information were used (age 43 ± 13 years; 49% men). Over the 20-year period, 26.3% (95%CI 24.4%, 28.3%) of participants developed T2DM; men exhibited a 1.5-times higher incidence compared to women (p < 0.001). Individuals consistently close to the Mediterranean diet throughout the studied period had an improved glycemic and lipidemic profile (at baseline and at 10-y follow-up) (all p-values < 0.001) and showed a 21% reduction in their 20-year risk of developing T2DM compared to those who were consistently away (RR = 0.79, 95%CI 0.47, 0.86). A long-term adherence to the Mediterranean diet is protective against the onset of T2DM and, therefore, could be incorporated in public health actions for the prevention of the disease.

Background: Epidemiological evidence consistently links higher consumption of red and processed meat with increased risk of type 2 diabetes (T2D) and adverse cardiometabolic outcomes, whereas dairy intake—particularly full-fat and fermented varieties—has shown neutral or protective associations. Understanding how substituting meat with dairy influences long-term metabolic and cardiovascular health can inform dietary recommendations and refine risk prediction models. Objective: This mini-review summarizes current epidemiological and mechanistic evidence on the modelled substitution of meat with dairy products in relation to T2D and broader cardiometabolic risk, with particular emphasis on findings from large-scale prospective studies. Evidence synthesis: Substitution analyses from multiple cohorts, including ATTICA, EPIC, and the Nurses’ Health Studies, indicate that replacing one daily serving of red or total meat with dairy—especially fermented or full-fat forms—tends to reduce T2D risk by approximately 15–40% and may favorably influence lipid and blood pressure profiles. Proposed mechanisms include improved lipid and glucose metabolism, enhanced insulin sensitivity, modulation of the gut microbiota, and attenuation of systemic inflammation and oxidative stress, through dairy-derived bioactive compounds such as calcium, vitamin D, odd-chain fatty acids, and probiotics. Conclusions: Current evidence suggests that replacing meat with dairy products, particularly fermented and full-fat types, may modestly reduce long-term cardiometabolic risk, including T2D. This substitution framework highlights the importance of dietary quality and food-source replacement, offering a practical, evidence-based approach to metabolic and cardiovascular disease prevention.