**3. The Mediterranean diet as a plausible intervention for preventing the incidence of diabetes**

The Mediterranean diet is the most widely discussed and historically significant plant-based diets of all. The Mediterranean diet is a homogeneous and straightforward construct having its roots in southern European eating patterns. The typical Mediterranean diet, which was first postulated by Ancel Keys in the 1960s [8], is characterized by high intakes of mono-unsaturated fatty acids, vegetables and fruits, plant proteins, whole grains, fish and low-fat dairy products, moderate alcohol (red wine) intake, and low red meat consumption [9]. Following this dietary consumption has demonstrated a reduced risk of mortality associated with mostly neurodegenerative diseases [9, 10]. According to the systematic review by Schwingshackl et al. [9], it was revealed that a significant association between adherence to dietary patterns exhibiting specific Mediterranean diet characteristics and decreased risk of type 2 diabetes. With respect to potential mechanisms of action, there appears to be a causal link between oxidative stress, inflammation, endothelial dysfunction, and diabetes when following this dietary pattern [11]. The Mediterranean diet has also shown a durable effect on circulating levels of C-reactive protein (CRP) and adiponectin in subjects with newly diagnosed type 2 diabetes [12]—an aspect, which is directly related to anti-inflammatory activities.

An observational study aimed to explore a possible relationship between the incidence of gestational diabetes mellitus and the Mediterranean diet pattern of eating was conducted by Karamanos et al. [13]. In this study, in 10 Mediterranean countries, 1076 consecutive pregnant women underwent a 75-g oral glucose tolerance test (OGTT) at 24–32 weeks of gestation, interpreted both by the American Diabetes Association (ADA) 2010 and the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) 2012 criteria. Adherence to a Mediterranean dietary pattern of eating was found to be associated with lower incidence of gestational diabetes and better degree of glucose tolerance, even in women without gestational diabetes.
