**9. A healthy model**

A healthy model, the latest 4-year winner, as the best nutritional model (US News and World Report 2021) is a Mediterranean model (Med Diet).

**Mediterranean model**: Like was firstly described by Ancel Keys on the occasion of Seven Countries Study, Med Diet is a plant-based diet, with abundant seasonal vegetables, fresh fruits as deserts, olive oil as the main source of fats, fish for 2–3 times/week, regularly nuts and seeds, daily whole cereals, dairies many times per week, red meat only rare, spices and herbs for tasty recipes. The important feature is unprocessed food cooked at home or in small restaurants, in antagonism with the Western diet, characterized mainly by highly processed food [9]. The uniqueness of this model derives from the combination of biologically active foods, with the right proportion between sources of fat, proteins, starches, fibers, minerals, vitamins, and bioactive compounds.

#### **9.1 What are the mechanisms supporting these benefits? Several clinical pathways and molecular mechanisms have been studied, suggesting beneficial changes induced by this dietary pattern**

Oxidative stress reduction and anti-inflammatory properties are attributed to bioactive components of food. The high content of polyphenols and low diet inflammatory index (DII) are correlated with all benefits. For example,


to increased production of butyrate, acetate, and propionate [14]. High-fiber content is another hallmark of the Med Diet. It has to be mentioned that 2 h of psychological stress may change completely gut bacteria. Butyrate-producing bacteria are increasing the quality of life.

#### **9.2 Studies supporting med diet**

Historically, the first study was done in the years 50, Seven Countries Study, which launched the concept defined by Angel Key, Med Diet. Later, Predimed, SUN, and LION are studies that proved different benefits of this eating model.
