From the ethical point of view, obviously vegan diet. Recently I knew that those who are in veg diet (or to say it in other words, live, because it is a way of living) have less issues with health (especially less cancer accidents, heart illnesses, hypertonia, and holesterine).
The more people who are in vegan diet, the more animals we save. I am not a vegan, but one day I'll become him. It's a matter of time. And because of some diseases I am unable to change my food habits. It's temporarily.