The simplest logic put forth by non-meat eaters is that the human stomach is not equipped to digest meat as well as it digests vegetables and other non-meat foods.
The debate goes on, sometimes violent in its beliefs, at other times with scientific evidence in tow. There are various reasons for this diverse thinking, the most common of them being the geographical, racial and hence cultural factor. Races born to live in low vegetation areas, naturally survived on meats and animal products while the inhabitants of the green planet could do with fruits, vegetables. Similarly those who lived by the water bodies for thousands of years developed a taste for seafood, which may or may not be shared by the inlanders. While it is a fact that food preferences are largely individual, this has not stopped the debate from becoming one of the longest topics of discussion in the civilized world. Statistics claim that almost 7% of the population of Europe, a traditionally meat eating culture, has turned vegetarian, including the Prince of Wales.
The arguments in favor of eating meat are varied and many. The most important among them is based on the belief that animal protein provides the best nutrition to the human body. The answer given for arguments against meats on moral grounds, are also interesting. Who, non-veggies argue, has the right to decide what's morally true? Lions hunt deer, is it moral or immoral? Nature has vested hunting rights in the strongest, by brawn or by brain. So humans score somewhere near the top, in brains of course. Then why is killing and eating animals wrong? Besides, connecting spirituality, a sense of morality and ethics with food habits does not appeal to everyone.
In Indian philosophy, what we eat affects our thoughts, through our body chemistry. Hence the three types of temperaments corresponds to three types of diets - satvik (pure), rajasik (royal - spicy, hot, highly flavored and exciting - meats fall in this category), and tamsik (dark elements, stale food, dark-colored foods that excite negativity) Of course, these are lose descriptions or the innocent burger will fall into the third category, owing to preserved meats in it! But loosely, yes, our food does affect the way we think. Which is why spiritual leanings discourage non-vegetarian and stale food.
Another strong argument that vegetarians make is that animals reared for their meat are kept in horrible conditions, often being slaughtered in inhuman (sic) conditions, effectively slaves. Their slaughter is often amidst horrific cruelty, where the animal dies thrashing in agony...and the argument is, how can we eat the meat of a creature that we have killed this way? If we encourage meat eating, aren't we encouraging these practices?
On more relevant levels, the idea is that meat based diets are often not good for health. There is a higher risk of colon cancer and other chronic diseases where meat is the main diet. But this may not be a very valid argument because here it is being assumed that a meat eater eats only meat, no fiber or starch or any other nutrients, other than high protein. In that case, toxins in the blood stream, slow digestion and putrefaction in the digestive tracts are possible. Some types of cancers are known to be attributed to a meat rich diet, rather, an unbalanced diet. But if a meat diet is supplemented by some foods rich in fiber and carbohydrates, these risks can be done away with. Of course, there are reports that a vegetarian diet lowers the risk of heart disease, obesity and increases life expectancy, but again, it does not seem to be supported by conclusive evidence. It would seem that diet rich in folic acid ensure longevity. As we see that the worlds longest living people come from Mongolian races, majorly fish and rice eaters. So then, what is the truth?
The truth lies somewhere in between. While it is true that vegetables contain some extremely healthy inputs like lower saturated fats, a higher concentration of folates, antioxidants and vitamins such as C and E, as well as a higher percentage of complex carbohydrates, it is evidently not the whole picture. A lot depends on the type of diet being followed. While vegetarians by and large will have a lower BMI, and lower cholesterol levels, there are a number of other factors involved in keeping them healthy and disease free. Exercise, adequate protein consumption and lower consumption of grease are some of the additional factors.
Scientists agree that the bacterial environment of the colon differs in vegetarians and non-vegetarians and this could be one reason for a lesser incidence of colon related diseases, particularly cancer, in vegetarians. Another study has revealed that across cultures, breast cancer rates are also lower in vegetarian populations. Prevention and treatment of renal cancer may also be more effective in vegetarians.
On the other hand, protein intake in vegetarians may be lower than meat eaters and may need to be supplemented; dairy products can do the trick. Vegetable products have a higher fat content but almost no cholesterol, and that includes the tiny members like peanuts too. Animal products, on the other hand, are loaded with cholesterol. Meat diets, however, do not only give in nutrition, but also all the toxins contained in the animal's body, the un-eliminated waste products and infections, including the disease carrying ones. Besides, an animal about to be slaughtered secretes hormones like epinephrine, norepinephrine and steroids, all severely toxic in nature. Plants do not even come close to this. One mention is made of hamburgers being made from cows with four Ds - Dead, Dying, Disabled or Diseased ... and this sounds just like a horror story, considering how much we all relish our hamburger.
Another fact is that boric acid is widely sprayed on fish, prawns and other crustaceans to preserve them, adding to their toxicity.
Meat eaters argue that plants and vegetables go through similar insecticide spraying, but then, plants don't secrete hormones and then release toxins to counter them!!!
Apart from all these, human bodies are not biologically equipped to eat meat. Carnivorous animals have intestines, liver and kidney to support the digestion of their food, but man has the intestines of a herbivore - very long. Besides, humans do not have claws and pointed teeth to help eat meat.
All these arguments for or against eating meat fall flat in the face of one single premise, personal choice. There are people who just cannot do without eating meat, and then there are those who cannot tolerate meat, whatever may be its virtues. There are religions and spiritual groups, indeed, religions like Buddhism which extol the virtues of not eating meat and animal products, and then are religions like Hinduism where eating or not eating meat is a matter of caste, region, time of the month, season, day of the month, marital status, penance and a multitude of other reasons. Most of these, in many cases, are forgotten in the company of meat eating friends...and a pure vegetarian at home is a perfect carnivore when eating out. As I said before, each to his own...as long as one has the virtue of standing by one's beliefs.