From the Mayo Clinic site about the Mediterranean Diet:

The Mediterranean diet is a way of eating based on the traditional cuisine of countries bordering the Mediterranean Sea. While there is no single definition of the Mediterranean diet, it is typically high in vegetables, fruits, whole grains, beans, nut and seeds, and olive oil.

The main components of Mediterranean diet include:

• Daily consumption of vegetables, fruits, whole grains and healthy fats
  
• Weekly intake of fish, poultry, beans and eggs
  
• Moderate portions of dairy products
  
• Limited intake of red meat

Other important elements of the Mediterranean diet are sharing meals with family and friends, enjoying a glass of red wine and being physically active.