Yes, canned tuna is permitted on the Mediterranean diet which emphasizes eating primarily plant-based foods, such as fruits and vegetables, whole grains, legumes and nuts, and prefers lean protein sources such as fish and poultry. The Mediterranean diet also encourages replacing butter with healthy fats such as olive oil, and using herbs and spices instead of salt to flavor foods. Hence, canned tuna, especially varieties packed in olive oil, fits well within this diet schema.