Mediterranean diet
The diet is based on what peasants, people who worked on farms, in countries around the Mediterranean Sea would eat during the Middle Ages and later, for example, Italian farm workers.  They ate a lot of olive oil, beans, and whichever fresh vegetables were growing at that time of year.  Meat was expensive, so it was not the main part of the meal. The Mediterranean diet does have foods from North and South America, for example tomatoes.