By going vegetarian, you go lower down the food pyramid. This means less energy contained in the food is wasted and more of it becomes available to our body's metabolic processes.

Let me illustrate this by an example. If you eat wheat directly, much of the energy that the wheat plant stored in its grains will enter you upon the wheat food getting digested.

But if you feed the wheat grains to chicken, cows or pigs first and then kill and eat them, more than 90 per cent of the energy in the wheat will be unavailable to you as that would be used up by the chicken, cows, etc., in keeping alive, in powering their movements, and in waste - the digestive system of these animals absorb only a small portion of the nutrients in the wheat, the rest is excreted. Also, quite a bit of the nourishment in the wheat that they do absorb will be used to generate inedible parts of their bodies such as feathers, bone, hair, hooves, blood, etc. Thus, taking all these into consideration, only about 10 per cent of the energy in wheat will become available to you if you eat animals fed on wheat.

Now consider the environmental implications of this. If you eat wheat directly, you will need only 10 per cent of the land currently cultivated for wheat. The remaining 90 per cent only feeds cattle, poultry, etc. When this agricultural land is freed of cultivation, it can revert back to natural forests which can then foster wildlife and help in carbon sequestration.

Or, the surplus wheat that will be available from the 90 per cent of land under wheat cultivation can be used to remove hunger from large parts of the world. We are in fact, contributing to keeping the world hungry by eating meat.

Also physiologically, our make-up is that of vegetarian animals. We don't have large canines to tear up meat, but prominent and large incisors that vegetarian animals have and use to shear grass and other plant material. We have strong molars to chew cellulose rich plant material and strong jaw muscles to help with chewing. In contrast, most carnivorous animals like lions, tigers and dogs, don't have jaw arrangements that facilitate chewing; they just bolt down food without chewing.

Also we have a conveyor belt kind of denture as are found in vegetarian animals like elephants. All our molars don't appear at the same time, but in stages. While 28 of our 32 teeth are in place by the time we are out of our teens, the last four molars appear when we are well into middle age. This is a strong indication that we were modelled for a vegetarian diet. Vegetarian diet is rich in roughage and cellulose which requires a lot of chewing to make it digestable. This chewing can wear out our teeth. To reduce the wear out suffered by our denture and to increase our chances of survival, nature has arranged that the last four of our molars will appear later in our lives, so that we remain toothful for a longer part of our lives.

And the last physiological argument in favour of vegetarianism is the structure of our stomach. We have a much more elaborate digestive system than that found in carnivorous animals. We have a very long small intestine and a fairly long large intestine that indicate our digestive system is tailored for digesting large quantities of plant-based food.

There are other arguments, too, in favour of vegetarianism. Vegetarian food is less dangereous as it contains less cholesterol. It is more balanced as it has plenty of vitamins, minerals and other micro-nutrients. So switching to vegetarian food can reduce chances of a host of diseases like heart ailments, diabetes, colon cancer and so on.

The strongest argument against meat-eating is ethical. How right is it for us to kill and eat large sentient beings like goats, sheep, cows and whales? Especially when after the discovery of agriculture we have an alternative form of plant-based food that can sustain us.