If natural is better should we follow Mother Nature?

Vegetarians in India have been branded as fanatics after the killing of a Muslim man in UP, allegedly for eating beef. Because most news reporting in India is biased and sensational we do not know whether the man was attacked for stealing cows, which cost a lot of money, or for eating meat. The debate on eating meat has become religious when it should be based on rational logic. We can dispense with God straight away because God must have created all the predators we see today. Predators appeared at the beginning of life on earth and have played a crucial role in evolution. So, if not God, what about morality? Is it moral to cause pain to an animal for food? Hindus slaughter animals by beheading it in one blow. Does it cause pain? Millions of human beings have been beheaded in history. During the French revolution the guillotine was used almost on an industrial scale. Charles I of England was beheaded with an axe. Today the ISIS uses a scimitar for beheading its victims. There is no study to see if victims of beheading suffer any pain but we can conjecture that, as the cells of the sensory cortex die off, there could be intense pain for some seconds. So, should we subject an animal to pain just for food? The question then arises as to whether death from natural causes, such as old age, cancer, stroke or heart failure, is painless. Ischemic pain is so severe that it needs intravenous morphine for relief. There was great rejoicing when passive euthanasia was allowed in India by the Supreme Court. Animals cannot talk so will have to suffer unnecessary pain from illness. Nature does not allow such suffering. In the wild, an old or sick animal will be killed by predators. Even a sick lion will be killed by other lions or by hyenas. Perhaps, stunning, as practiced in the west, is the most humane way of slaughter. Surely, eating meat is bad for health? Not so. Gujarat, which has probably the largest number of vegetarians, has the highest rates for diabetes and hypertension in India. Raising animals is very bad for the environment, right? Cows are said to be methane factories, which is worse than producing CO2. Trouble is that vegetarians in India consume large quantities of cow's milk and milk products. Farm animals cause depletion of natural resources, such as water. Rice takes a lot of water to cultivate and farmers burn the stubble after harvesting, creating severe pollution. Because it is difficult to obtain the same nutrition from a plant based diet you need much more land which means destruction of forests. The haze in south east Asia is for producing palm oil. Pesticides are highly toxic and poison water sources. Finally, meat eating animals are much more intelligent than grass eaters. If humans become vegetarians we may evolve backwards into goats. Do we really want that?