By Archbishop Nikephoros Theotokis (+ 1800)
Those who avoid fasting, fearing they will harm their health, they are unlearned and of little faith, not knowing what is true fasting, thinking that fasting is the abstention only of four or six types of foods. When we fast, we search the earth and sea up and down: the earth in order to collect seeds, produce, fruit, spices, and every other kind of growing edible; the sea to find shellfish, mollusks, snails, sea-urchins, and anything edible therein. We prepare dry foods, salted foods, pickled foods, and sweet foods, and from these ingredients we concoct many and motley dishes, seasoned with oil, wine, sweeteners, and spices. Then we fill the table even more than when we are eating meat. Moreover, since these foods stimulate the appetite, we eat and drink beyond moderation. And after this we imagine that we are fasting. Such fasting truly does harm, because the aforesaid foods are indigestible, unwholesome, spicy; from these they become juicy, undigested, of a bad temperament, salty, acidic. Thus from these come indigestion, an unhealthy state of the humors, saltiness, spiciness and many other bothersome diseases of the soul and body.
And who ever taught those who fast in this way that such a variety and such quantities of food constitute a fast? Where did they read or hear that anyone who simply avoids meats or fish is fasting, even if he eats a great amount and different kinds of food? Fasting is one thing, great variety in food another; fasting is one thing, eating great amounts of food another. Fasting is total non-eating or eating one meal or eating dry foods. When you do not eat from morning till evening, then you are fasting; when you do not eat anything except one portion of food, or bread, or vegetable, or fruit, or legumes, and these without flavoring, then you are fasting. Such fasting not only in no way causes harm, but it is also very beneficial. The ascetics and hermits always fasted this way, and were still healthy, living long lives; such fasting is a very beneficial diet. Wise physicians place their hopes in these, as well as in herbs, for they heal many and various forms of sicknesses.
Source: Homily for Cheesefare Sunday.