The original study [1] doesn't say it was plant based at all:
> the Mediterranean diet score ranged from 0 to 9, with a higher score representing better adherence to Mediterranean diet. This Mediterranean diet score is commonly used for assessing adherence to the Mediterranean diet and is based on regular intake of 9 dietary components. Higher-than-median intake of vegetables (excluding potatoes), fruits, nuts, whole grains, legumes, and fish and the ratio of monounsaturated-to-saturated fatty acids was given 1 point, while the less-than-median intake of red and processed meat was given 1 point.
> the Mediterranean diet score ranged from 0 to 9, with a higher score representing better adherence to Mediterranean diet. This Mediterranean diet score is commonly used for assessing adherence to the Mediterranean diet and is based on regular intake of 9 dietary components. Higher-than-median intake of vegetables (excluding potatoes), fruits, nuts, whole grains, legumes, and fish and the ratio of monounsaturated-to-saturated fatty acids was given 1 point, while the less-than-median intake of red and processed meat was given 1 point.
So not plant based, not even vegetarian!
[1] https://jamanetwork.com/journals/jamanetworkopen/fullarticle...