Adequate intake of proteins, fats, vitamins, minerals and fluids necessary for the normal functioning of the human body is essential in a proper diet. The diet of the ancient Greeks was simple, and this can be seen on the basis of data from selected ancient sources (Homer, Alcaeus, Sappho, Herodotus, Hippocrates, Aristophanes, Xenophon, Aristotle, Theophrastus, Strabo, Archestratus, Dioscorides, Plutarch and Oppian). In this paper focus is on basic food which Greeks used in their diet (cereals, fruits and vegetables, spices, honey, fish, meat, milk), how they received, prepared and stored food, what their main meals consisted of (breakfast, lunch, dinner), what kind of food was served on festive occasions (drunkenness/feasts, weddings and funerals) and what symbolic meaning was attributed to certain foods on those occasions. At the end of the paper, the diet of soldiers is described and the principles of healthy eating by the famous Greek physician Hippocrates, who can be considered the originator of nutrition, today a relatively young scientific discipline, are presented.