Although some historians and anthropologists say that man is historically omnivorous, our anatomical equipment . teeth, jaws, and digestive system favors a fleshless diet. The American Dietetic Association notes that "most of mankind for most of human history has lived on vegetarian or near-vegetarian diets."

And much of the world still lives that way. Even on most industrialized countries, the love affair with meat is less than a hundred years old. It started with the refrigerator car and the twentieth-century consumer society. But even with the twentieth century, man's body hasn't adapted to eating meat. The prominent Swedish scientist Karl von Linne states, "Man's structure, external and internal, compared with that of the other animals, shows that fruit and succulent vegetables constitute his natural food." The chart below compares the anatomy of man with that of carnivorous and herbivorous animals.

When you look at the comparison between herbivores and humans, we compare much more closely to herbivores than meat eating animals. Humans are clearly not designed to digest and ingest meat.

Meat-eaters: have claws
Herbivores: no claws
Humans: no claws

Meat-eaters: have no skin pores and perspire through the tongue
Herbivores: perspire through skin pores
Humans: perspire through skin pores

Meat-eaters: have sharp front teeth for tearing, with no flat molar teeth for grinding
Herbivores: no sharp front teeth, but flat rear molars for grinding
Humans: no sharp front teeth, but flat rear molars for grinding

Meat-eaters: have intestinal tract that is only 3 times their body length so that rapidly decaying meat can pass through quickly
Herbivores: have intestinal tract 10-12 times their body length.
Humans: have intestinal tract 10-12 times their body length.

Meat-eaters: have strong hydrochloric acid in stomach to digest meat
Herbivores: have stomach acid that is 20 times weaker than that of a meat-eater
Humans: have stomach acid that is 20 times weaker than that of a meat-eater

Meat-eaters: salivary glands in mouth not needed to pre-digest grains and fruits.
Herbivores: well-developed salivary glands which are necessary to pre-digest grains and fruits
Humans: well-developed salivary glands, which are necessary to pre-digest, grains and fruits

Meat-eaters: have acid saliva with no enzyme ptyalin to pre-digest grains
Herbivores: have alkaline saliva with ptyalin to pre-digest grains
Humans: have alkaline saliva with ptyalin to pre-digest grains
Based on a chart by A.D. Andrews, Fit Food for Men, (Chicago: American Hygiene Society, 1970)

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