At the outset, Smith states that “we are vegetarians, because we think nature designed us to subsist on the ‘fat of the land,’ and not on the flesh and blood of beasts, or any living, sentient creature” (9). The titular “fat of the land” is not “the fat of beasts, and of every available creature that moves upon the earth, soars through the air, or swims in the sea, but that which Mother Earth bounteously yields to her children in every land and clime” (33). As she puts it, the “book is designed to meet not only the needs of radical dietetic reformers and vegetarians, but also to assist those who are thinking upon this question with special reference to the slaughter of animals for food” (242), particularly given that domestic animals “have been rendered so unlike their original selves, that their flesh and products have become dangerous and questionable as articles of food for the human family” (9). A vegan diet is economical and thus contributes to solving the problem of poverty (31). Given the ready availability of plant-based foods, “there is no excuse but the lack of effort to procure perfect substitutes for animal products” (245) and she answers this with her vegan recipes that include bread, biscuits, cereals, a variety of fruits and vegetables as well as nut used in many different ways.

For Smith, veganism is not merely a question of diet but has larger moral and social implications:

Vice begins in half-starved bodies. Crimes owe their parentage to starvation of brain and stimulation of mind and body in the wrong direction: these with unbalanced morals manifested in a multitude of ways, result in crime, war and intemperance. From a vegetarian standpoint, these unhealthful conditions of mind and body are largely propagated, nourished and developed from the never ending supply of slaughtered flesh and its stimulating – not nourishing – accompaniments. The moral and physical health of millions is thus undermined, and from such material is created generation after generation of imperfect human beings (12-13).

Temperance in all things leads to happiness, health, and a long and useful life” (17). She notes her connections with the water-cure movement, her graduation from “Dr. R. T. Trall’s College, New York City, in 1861,” and her subsequent work as an “experimental demonstrator in hygienic cookery, and bread making” (18).

More specifically: “Fruit and bread is an ideal and perfect diet; the variety sufficient to sustain health and life to a good old age, and with nothing else a royal feast may be provided daily” (28). She adds to this “fruits, nuts, grains, vegetables" that are "so abundantly stored with nutriment, so prolific in variety, why need we consume dead flesh, in which lurks poison at best, and disease difficult of detection by the average consumer” (31). A diet based on animal food is not natural but a “relic of barbaric ages” (33). She explains that since human anatomy is not “adapted to tearing and devouring flesh, including bones and skin ... it becomes more in harmony with the aspirations of a humane and civilized people to discard the use of animal food” (35). Smith claims “that vegetarians in any profession or occupation will endure more labor without weariness than the flesh eater,” “that athletes, gymnasts, runners, walkers, and cyclists who live and are trained on a vegetable diet, invariably – other things being equal – win the race or game, and at its close are not in the exhausted condition of their flesh-eating companions” (37), and that meat-eaters tend to be “quarrelsome, brutal and ferocious” (38).

Smith's opposition to animal agriculture, vivisection, hunting, and the use of meat for food is motivated by concern about the negative effects of cruelty on human morality. She anticipates “the day when the abattoir with its nameless horrors shall be banished, farmyard slaughter cease and kindness be a dominant, inborn characteristic of the race” (228). “Thus,” she continues, “it will be seen that the trend of our best thought and labor is directed toward the elevation of the human race and the humane treatment of the animal world” (230). She is particularly concerned about the impact of normalized cruelty on children:

If, then, school room dissections are so pernicious, such educators in cruelty and demoralizers of youth, so also must be farmyard slaughter and domestic dissections constantly practiced before our children, either directly or indirectly. And yet we have been so blinded by a carnivorous appetite, the discovery is but just dawning upon our minds that possibly hunting, fishing, trapping game and killing every available creature for food may have had an influence in producing the inharmonious conditions about us. To examine this matter a little more closely, think of the mothers, present and prospective, daily handling meats of some kind, dissecting, pickling, salting and cooking not only the flesh, but the internal organs, and serving them as food. And these are the mothers of the race, engaged in and constantly familiar with dissections (230).

In stark contrast, veganism “reveals a new code of ethics, that will bring peace to the body, that peace may prevail upon earth” (245). Notably, women have to be the vanguard in this respect:

Through woman must come this most vital change in the customs and habits of life. If she be the “homemaker,” let her be also the home and health-preserver. If she be the queen of the fireside, let her wield as a sceptre the magic wand that will purify and glorify the home. She will then be no longer a slave, pleading for her “rights;” [sic] no longer under bondage to pills, potions and patent nostrums, and the visits of the family physician will be few and far between. Not only would be seen revolution and revelation healthward, but improvements in our social, moral and business life. Revolution in the inebriate and criminal calendar that would be mighty revelations to that large portion of humanity who are striving to “make the world better” (43).