Fleisch vs. Vegetarisch

In Bezug auf die richtige, die 'natürliche' Ernährung gibt es ja tausende von Theorien.
Die Yoga-Schriften empfehlen eine Ernährung ohne Fleisch, Fisch, Eier, aber dafür mit Milchprodukten. Mal wird gesagt, daß man Knoblauch und Zwiebeln vermeiden solle, man wird der Verzehr davon explizit empfohlen (s. Yesudian).
Dann haben zumindest in westlichen Ländern heutzutage viele Leute eine gewisse Laktose-Unverträglichkeit, verzichten dementsprechend auf Milchprodukte.
Ähnlich gibt es auch mit Gluten. Dann kann man viele Getreidearten nicht essen.
In den USA ist in den letzten Jahren die sogenannte 'Paleo Diet' populär geworden. Die Philosophie ist ungefähr so, daß die Menschen erst in den letzten 10.000 Jahren Ackerbau betrieben haben. In den Hunderttausenden von Jahren zuvor waren die Menschen aber Jäger und Sammler. Unser Körper ist immer noch von der Struktur und den Bedürfnissen der des Jägers und Sammlers, daher auch die Unverträglichkeit von Milch- und Getreideprodukten. Anhänger der Paleo Diet verzichten auf alle Getreideprodukte und ernähren sich vorwiegend von Obst, Gemüse, Fleisch, Fisch und Nüssen. Dabei ist hervorzuheben, daß sie das Fleisch aus der Massentierhaltung ablehnen und z.B. nur Rind essen, das Gras auf der Wiese gefressen hat im Gegensatz zu Getreide- oder anderer Kraftnahrung.
Was ist nun richtig? Ich denke, jeder muß es selber entscheiden. Gute Beobachtung, was einem bekommt und ein intuitives Gespür für die Verträglichkeit von Lebensmitteln sind besser als rigides Klammern an Theorien.
Neben der physiologischen Komponente gibt es dann natürlich auch noch die ethische und die Geschmackskomponente.

Zur Frage, ob Menschen aus biologischer Sicht eher als Fleisch- oder als Pflanzenfressen einzuordnen sind, fand ich diesen Artikel interessant:

The animals most similar to us, the other primates, eat an almost exclusively vegetarian diet (and their main non-plant food often isn’t meat, it’s termites).

Our teeth, saliva, stomach acid, and intestines are most similar to other plant-eaters, and dissimilar to carnivores and true omnivores.

Among animals, plant-eaters have the longest lifespans, and humans are certainly in that category (and yes, this was true even before modern medicine).

We sleep about the same amount of time as other herbivores, and less than carnivores and true omnivores.

Meat-Eaters

Carnivorous animals, including the lion, dog, wolf, cat, etc., have many unique characteristics which set them apart from all other members of the animal kingdom. They all possess a very simple and short digestive system — only three times the length of their bodies. This is because flesh decays very rapidly, and the products of this decay quickly poison the bloodstream if they remain too long in the body. So a short digestive tract was evolved for rapid expulsion of putrefactive bacteria from decomposing flesh, as well as stomachs with ten times as much hydrochloric acid as non-carnivorous animals (to digest fibrous tissue and bones). Meat-eating animals that hunt in the cool of the night and sleep during the day when it is hot do not need sweat glands to cool their bodies; they therefore do not perspire through their skin, but rather they sweat through their tongues. On the other hand, vegetarian animals, such as the cow, horse, zebra, deer, etc., spend much of their time in the sun gathering their food, and they freely perspire through their skin to cool their bodies. But the most significant difference between the natural meat-eaters and other animals is their teeth. Along with sharp claws, all meat-eaters, since they have to kill mainly with their teeth, possess powerful jaws and pointed, elongated, “canine” teeth to pierce tough hide and to spear and tear flesh. They do NOT have molars (flat, back teeth) which vegetarian animals need for grinding their food. Unlike grains, flesh does not need to be chewed in the mouth to predigest it; it is digested mostly in the stomach and the intestines. A cat, for example, can hardly chew at all.

Plant-Eaters

Grass-and-leaf-eating animals (elephant, cow, sheep, llama, etc.) live on grass, herbs, and other plants, much of which is coarse and bulky. The digestion of this type of food starts in the mouth with the enzyme ptyalin in the saliva. these foods must be chewed well and thoroughly mixed with ptyalin in order to be broken down. For this reason, grass-and-leaf eaters have 24 special “molar” teeth and a slight side-to-side motion to grind their food, as opposed to the exclusively up-and-down motion of carnivores. They have no claws or sharp teeth; they drink by sucking water up into their mouths as opposed to lapping it up with their tongue which all meat eaters do. Since they do not eat rapidly decaying foods like the meat eaters, and since their food can take a longer time to pass through, they have much longer digestive systems — intestines which are ten times the length of the body. Interestingly, recent studies have shown that a meat diet has an extremely harmful effect on these grass-and-leaf eaters. Dr. William Collins, a scientist in the New York Maimonedes Medical Center, found that the meat-eating animals have an “almost unlimited capacity to handle saturated fats and cholesterol”. If a half pound of animal fat is added daily over a long period of time to a rabbit’s diet, after two month his blood vessels become caked with fat and the serious disease called atheriosclerosis develops. human digestive systems, like the rabbit’s, are also not designed to digest meat, and they become diseased the more they eat it, as we will later see.

Fruit-eaters include mainly the anthropoid apes, humanity’s immediate animal ancestors. The diet of these apes consists mostly of fruit and nuts. Their skin has millions of pores for sweating, and they also have molars to grind and chew their food; their saliva is alkaline, and, like the grass-and-leaf eaters, it contains ptyalin for predigestion. Their intestines are extremely convoluted and are twelve times the length of their body, for the slow digestion of fruits and vegetables.

Human Beings

Human characteristics are in every way like the fruit eaters, very similar to the grass- eater, and very unlike the meat eaters. The human digestive system, tooth and jaw structure, and bodily functions are completely different from carnivorous animals. As in the case of the anthropoid ape, the human digestive system is twelve times the length of the body; our skin has millions of tiny pores to evaporate water and cool the body by sweating; we drink water by suction like all other vegetarian animals; our tooth and jaw structure is vegetarian; and our saliva is alkaline and contains ptyalin for predigestion of grains. Human beings clearly are not carnivores by physiology — our anatomy and digestive system show that we must have evolved for millions of years living on fruits, nuts, grains, and vegetables.

Furthermore, it is obvious that our natural instincts are non-carnivorous. Most people have other people kill their meat for them and would be sickened if they had to do the killing themselves. Instead of eating raw meat as all flesh-eating animals do, humans boil, bake, or fry it and disguise it with all kinds of sauces and spices so that it bears no resemblance to its raw state. One scientist explains it this way: “A cat will salivate with hungry desire at the smell of a piece of raw flesh but not at all at the smell of fruit. If man could delight in pouncing upon a bird, tear its still-living limbs apart with his teeth, and suck the warm blood, one might conclude that nature provided him with meat-eating instinct. On the other hand, a bunch of luscious grapes makes his mouth water, and even in the absence of hunger he will eat fruit because it tastes so good.”

Scientists and naturalists, including the great Charles Darwin who gave the theory of evolution, agree that early humans were fruit and vegetable eaters and that throughout history our anatomy has not changed. The great Swedish scientist von Linné states: “Man’s structure, external and internal, compared with that of the other animals, shows that fruit and succulent vegetables constitute his natural food.”

So it is clear from scientific studies that physiologically, anatomically, and instinctively, man is perfectly suited to a diet for fruit, vegetables, nuts, and grains.