Whilst I love your caring, sympathetic approach towards animal slaughter, I don't think animals willingly give their lives at all. The murderers take them without permission. They don't volunteer to line up in factories/held down/strung upside down on farms knowing they'll be killed to become food.

The human body was designed to consume a lot of things, not only meat. Interestingly, we cannot eat most meats raw, we have to cook the meat as opposed to naturally serving it raw like we can with fruit. Other foods we cook, like French fries and bread for instance are still edible raw unlike a freshly shot animal carcass.

Animals do not give their lives for us to live, we can live without eating them. Red meat is known to contribute to disease.