The Greek diet was very healthy. Food in Ancient Greece consisted of grains, wheat, barley, fruit, veggies, breads and cake. They also grew olives, grapes, figs, wheat and kept goats for milk and cheese. In the summer months they would east lots of fish and squid. From what I can tell they were pescatarian . Because their diets did not consist of meat, but rather fish. They felt killing and eating domesticated animals was wrong.
Pescatarian diet.
Hope this helps!