This section is from the book "The Natural Food Of Man", by Emmet Densmore. Also available from Amazon: How Nature Cures Comprising a New System of Hygiene.
The consensus of writers, from the time of the Greeks to the present day, unite in saying that the primitive peoples had health and vigour; while it has been reserved for Civilisation to breed diseases whose names are legion, and to witness imbecility, decrepitude, and premature death go hand in hand with luxury and plenty. The race has strayed far from the path of health and peace; and most likely must return by the route whence it came : (1) Discontinue the use of cereals and vegetables, and the multitudinous cookings and concoctions to which the use of these products give birth; (2) Make fruits and nuts the basis of human food, supplemented by such animal products, with the minimum of cookery, as in the present condition of the race may be found necessary; (3) An absolute return to nuts and fruits, uncooked and unseasoned. After which there will be no diseases, and no doctors, upon the face of the earth.
"It is one of nature's laws, and a very simple one, that we are built up from what originally was vegetable albumen; and, with the exception of the alkaline and earthy salts, every structure and organ in our bodies was developed from and is nourished by albumen. It was one of the laws of Eden that man should eat albumen - vegetable albumen - in its purest form, as it exists in fruits.
"There is, therefore, a simplicity, a reason, a wonderful philosophy in the first command given to man. Man may live entirely upon fruits, in better health than the majority of man-kindnow enjoy. Good, sound, ripe fruits are never a cause of disease; but the vegetable acids, as we have before stated, lower the temperature of the body, decrease the process of combustion or oxidation - therefore the waste of the system - less sleep is required, activity is increased, fatigue or thirst hardly experienced: still the body is well nourished, and, as a comparatively small quantity of earthy salts are taken into the system, the cause of 'old age' is in some degree removed, the effect is delayed, and life is prolonged to a period far beyond our 'threescore years and ten.'
"Animal flesh, taken as a class, contains, next to fruits, the least amount of earthy salts. . . .
"The amount depends, firstly, upon the quantity contained in the food of the animal; secondly, upon the duration of time the animal has eaten such food - that is, its age. Younger animals of every class contain a less amount of earthy salts in their flesh than older ones; thus veal, in the analyses generally given, contains only about one-fourth the amount of earthy salts found in an equal weight of the flesh of an adult animal, and it further contains from 12 to 15 per cent, more phosphoric acid than is necessary for the formation of salts. . . .
"'The true unsophisticated American Indians near the sources of the Missouri, during the winter months, are reported to subsist entirely upon dried buffalo flesh - not the fat portions, but the muscular part. . . . During their subsistence on dried pemmican, they are described by travellers, who were intimate with their habits of life, as never tasting even the most minute portions of any vegetable whatever, or partaking of any other variety of food. These facts, then, tend to show that albuminous tissue is of itself capable of sustaining life.' - Dr. Thompson.
"In other articles of animal food we have milk, unskimmed, skimmed, and buttermilk; they all contain about 7 per cent, of salts; but the latter contains a large quantity of lactic acid, which has a great tendency to prevent the accumulation of earthy matter in the system.
"Cheese contains salts in about the same proportion as milk deprived of its water. It seems by its analysis to have a large quantity of salts (nearly 5 per cent.), but they exist in ratio to its highly nourishing properties.
"Eggs contain 1.5 per cent. of salts (.5 per cent.less than beef and mutton). .
"The cereals constitute the basis of man's food; they mostly con'ain large quantities of mineral matter, and as a class are the worst adapted as a food for man, in regard to a long life. Man's so-called 'staff of life' is, to a great extent, the cause of his premature death.
"In the twenty-second and twenty-third chapters of the Third Book ('Thalia') of Herodotus, describing a visit of some Persian Ambassadors to the long-lived Ethiopians (Macrobii), the Ethiopians asked what the Persian King was wont to eat, and to what age the longest-lived of the Persians had been known to attain. They told him that the King ate bread, and described the nature of wheat - adding that eighty years was the longest term of man's life among the Persians. Hereat he remarked," It did not surprise him. if they fed on dirt (bread), that they died so soon; indeed, he was sure they never would have lived so long as eighty years except for the refreshment they got from that drink (meaning the wine), wherein he confessed the Persians surpassed the Ethiopians." The Ichthyophagi then, in their turn, questioned the King concerning the term of life and diet of his people, and were told that most of them lived to be a hundred and twenty years old, while some even went beyond that age : they ate boiled flesh, and had for their drink nothing but milk.' ....
"We, therefore, see that the different kinds of food, in regard to longevity, have the following order : fruits, fish, animal food (flesh, eggs, etc.), vegetables, cereals. In the same order do we trace the age of man by his diet. It is written that man in the first ages lived for a period which to us seems incredible; but in the present generation the average time of life is so short, that a man at eighty or ninety years is truly a modern 'patriarch.' Man's first and ordained diet was fruits; he then ate animal food, which was subsequently permitted to him; after this he gained a knowledge of agriculture - he grew vegetables and cereals; and, not content with this, during the last few years he has learned to add lime artificially to them - to shrink and lessen an already shortened existence.