The Greek diet was very healthy. Food in Ancient Greece consisted of grains, wheat, barley, fruit, vegetables, breads, and cake.
The Ancient Greeks grew olives, grapes, figs and wheat and kept goats, for milk and cheese. They ate lots of bread, beans and olives.
In the Summer months there were plenty of fresh fruit and vegetables to eat and in the winter they ate dried fruit and food they had stored like apples and lentils. As most of the Greeks lived very near the sea, they also ate a lot of fish, squid and shellfish.
The soil by the sea was not so rich as on the plains so the Greeks used irrigation and crop rotation to keep the soil relatively fertile.
In some of the larger Greek city-states, meat could be purchased in cook shops. Meat was rarely eaten as the Greeks felt that just killing and eating a domesticated animal (like goats) was wrong. The Greeks would often sacrifice the meat to the gods first and then might eat some of the meat.
The Greeks loved their wine which was made from the grapes they grew.