In a state of nature man has to hunt his food, and the amount that he finds is generally limited, and requires a lot of exercise to get. Explorers in Africa give us a picture of man's life in the savage state, guided by his instincts and very little interfered with by reason. The savages will starve for long periods, then they will succeed in killing a hippopotamus or a buffalo, and they will gorge themselves, and nearly all of them will be ill, and several of them will die. So you see, even in a state of nature, and with natural foods, restraint is needed, and reason and moral sense have a part to play. What do reason and moral sense have to tell us about diet? Our bodily processes go on continuously, and we need at regular intervals a certain quantity of a number of different foods. The most elementary experiment will convince us that we can get along, maintain our body weight and our working efficiency upon a much smaller quantity of food than we naturally crave. Civilized custom puts before us a great variety of delicate and appetizing foods, upon which we are disposed to overeat; and we are slow observers indeed if we do not note the connection between this overeating and ill health. So we are forced to the conclusion that if we wish to stay well, we need to establish a censorship over our habits; we need a different diet regimen from the haphazard one which has been established for us by a combination of our instincts with the perversions of civilization. Up to a few years ago, it was commonly taken for granted by authorities on diet that what the average man actually eats must be the normal thing for him to eat. Governments which were employing men in armies, and at road building, and had to feed them and keep them in health, made large scale observations as to what the men ate, and thus were established the old fashioned "diet standards." They are expressed in calories, which is a heat unit representing the quantity of fuel required to heat a certain small quantity of water a certain number of degrees. In order that you may know what I am talking about, I will give a rough idea of the quantity of the more common foods which it takes to make 100 calories: one medium sized slice of bread, a piece of lean cooked steak the size of two fingers, one large apple, three medium tablespoonfuls of cooked rice or potatoes, one large banana, a tablespoonful of raisins, five dates, one large fig, a teaspoonful of sugar, a ball of butter the size of your thumbnail, a very large head of lettuce, three medium sized tomatoes, two-thirds of a glass of milk, a tablespoonful of oil. You observe, if you compare these various items, how little guidance concerning food is given by its bulk. You may eat a whole head of lettuce, weighing nearly a pound, and get no more food value than from a half ounce of olive oil which you pour over it. You may eat enough lean beefsteak to cover your plate, and you will not have eaten so much as a