Eating grains or so.... doesn'tmean no animals were killed in the process. Small animals, but still... during the harvest, thousands, nay, millions of ants... I'd rather kill a plant than an animal but what's one to do?
The food chain... the grains fed cows could feed us all... all 6 or is it now 7 billion people on this planet.
Better healthcare does extend the average lifespan in the West. Yet the tribes who live to ninety or a hundred or even more usualyl don't require much of that. They live natural lives, in touch with nature, and a healthy diet from mineral-rich soils and have much less oxidative stress on their bodies (fewer free radicals due to a more healthy lifestyle). I guess one's emotional state plays a great role too. hence also the ones who grow so old in the West who did just what they wanted. They do not worry and go more with the flow of life. Surely health and happiness are closely connected and influence each other. Balance that with a balanced diet and keep excesses to a minimum and you set yourself good odds that might help counter genetic predisposition... I experimented with vegetarianism and all sort of healthy for a while to the point that I had an internal list of good+bad foods all the time, and, frankly, one can take it too far, to a sort of odd pre-anorexic state where much enjoyment is lost, guilt felt, etc. but I went back not being a food-fascist any more and to enjoy more again. I tend to eat healthy at home except for occasional munchies when stoned (chocoalte attacks in the evening) but will eat almost anything I'm served when offered food outside. But I am picky with meat. I never buy it but do order chicken often when I eat out. The reason I eat it is because my body likes the energy it receives from it. It's easier for me to keep my strength if I eat chicken or fish occasionally.
Yet I believe that we do not NEED it and that the degree of our spiritual evolution can be measured by how we treat other, weaker, species. When we eat them, we are merely taking advantage because we can, bot because we need to. This says a lot about human nature, imo. Regarding plants- they are certainly alive but I hold the view that they are not sentient beings in the same sense as animals. Animals are very much like us.
http://en.wikipedia.org/wiki/Hunza <-- This tribe is said to be blessed with exceptional longevity (see "Hunza Diet" and "Hunza People")