The most commonly used operational definition of a MD is the Mediterranean Dietary score proposed by Trichopoulou et al. in 1995 [
16], which was updated in 2003 [
17]. The Mediterranean score is built by assigning a value of 0 or 1 to each of nine components with the use of sex-specific medians as the respective cutoffs. In detail, this MD score is characterized [
17] by six beneficial components (high consumption of vegetables, fruits and nuts, legumes, unprocessed cereals, fish, and a high ratio of monounsaturated fatty acids to saturated fatty acids) and two components regarded to be detrimental (meat and meat products including poultry and dairy products with the exception of cheeses preservable for a long period of time). With respect to favorable ingredients, persons whose consumption is at or above the median receive a score of 1 for each category, and persons whose consumption is below the median receive a score of 0. With respect to unfavorable ingredients, the scoring system is applied with reversed signification. The potential benefit of moderate alcohol consumption is taken into account by assigning a value of 1 to men who consume between 10 and 50 g per day and to women who consume between 5 and 25 g per day, respectively [
17]. The highest adherence to a MD is therefore represented by a maximum score of 9.
The second most widely used MD score is an alteration of the original score by Trichopoulou adapted by Fung et al. in 2006 [
18]. The following components were either excluded or modified: exclusion of potato products from the vegetable group, separation of fruits and nuts into two groups, exclusion of the dairy group, inclusion of whole-grain products only, inclusion of red and processed meats only in the meat group, and assignment of 1 point for alcohol intake between 5 and 15 g/day. In 2014, Whalen et al. [
19] modified this alternate MD score with respect to dairy foods, grains and starches, and alcohol intakes. Another variation of the score by Trichopoulou et al. [
17] was introduced by Tognon et al. [
20] and Xie et al. [
21] by adding fruit juices and polyunsaturated fatty acids, focusing on whole grains, and excluding poultry. The MD score established by Panagiotakos et al. in 2007 [
22,
23] is based on 11 main components (non-refined cereals, fruits, vegetables, potatoes, legumes, olive oil, fish, red meat, poultry, full-fat dairy products, and alcohol). Consumption of items adhering to this pattern will result in scores of 0, 1, 2, 3, 4, and 5 when a participant reported no, rare, frequent, very frequent, weekly, and daily consumption, respectively. Three of the 11 components were considered to exert detrimental effects (red meat, poultry, full-fat dairy products). For alcohol, a value of 5 is assigned to subjects who consume <300 ml (12 g ethanol) alcoholic beverages per day, and a value of 0 is applied if alcohol consumption is either >700 or 0 ml/day.
Other infrequently used MD scores include the Mediterranean Diet quality index [
24], the Mediterranean Score by Goulet et al. [
25], the Mediterranean Diet pattern score [
26], the Mediterranean dietary pattern adherence index [
27], and the Mediterranean Adequacy Index [
28].