People are most commonly classified as 'omnivores'. This classification was made after observing that humans had a wide variety of plant and animal foods in their diet. However, culture, customs and upbringing also have a major impact on the way we eat.
From this we see that observation is not the best technique to discover the most natural way of eating for man. Although most people are omnivorous by behavior, the question still arises as to whether a person, by his or her anatomy, is adapted to a diet that includes food of plant and animal origin.
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The human digestive tract (system) shows anatomical changes in accordance with the plant diet. People have muscular lips and a small mouth opening. Many of the muscles that form the so-called 'facial expressions' are actually involved in chewing. The muscular and agile language we need to eat has developed some other functions, such as participating in speech.
The jaw joint is flattened with cartilage and located well above the height of the teeth. The temporal muscle is weakened. The characteristic 'square jaw' in males reflects the expanded angular growth on the jaw and the expanded chewing and clamping muscle groups. The human jaw can move forward thanks to incisors and from side to side allowing for crushing and grinding of food.
Human teeth are also similar to those of herbivores, except for canines (canines are elongated in some monkeys and are considered to serve as a warning and / or defense). Our teeth are quite large and usually clenched together. The incisors are flat and shovel-shaped, and are useful for peeling, cutting and biting relatively soft materials.
Our canines are neither toothed nor conical, but are small, flattened and obtuse and function like incisors. The precursors and molars are somewhat square, flattened, lumpy, and are used for crushing, grinding and converting food into pulp.
Human saliva contains enzymes for the breakdown of carbohydrates, the so-called saliva amylase. These enzymes are responsible for the breakdown of starch. The esophagus is small and suitable for passing small, soft balls of well-chewed food. If we eat fast, ingesting large amounts of food or ingesting fibrous and / or poorly chewed foods (such as meat) we can suffocate.
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The human colon appears to be divided into sacs, which is also characteristic of herbivores. The stretchable colon is much larger in cross-section than the small intestine and is quite long. The human colon is responsible for the absorption of water and electrolytes and for the production and absorption of vitamins. There is also fermentation of fibrous plant material, with the production and absorption of significant amounts of energy (from non-persistent short chains of fatty acids).
The extent to which fermentation and absorption of metabolites take place in the human colon has only recently been investigated.
In conclusion, we can say that the structure of the human digestive system is the same as that of 'devotional' herbivores. The human species does not show mixed lines in the digestive material of what it would be expected and how we usually find in omnivores such as bears and raccoons.
Therefore, comparing the human digestive system with that of carnivores, herbivores and omnivores, we can conclude that the human digestive system is designed to digest only plant foods.
Imagine now that there are no more slaughterhouses, knives and butchers, and that you have come face to face with the cow you want to eat. You only have your natural weapon - your hands and your teeth - and you need to kill that cow to get to the food. Could you do that? Jump on her and bite her neck? Do you think a rabbit that is significantly smaller than a cow would go better? Even if you broke his neck, would you tear him with your own teeth?!?