Designed? By whom? Humans are not designed, humans have evolved, and continue to evolve. Humans also appear to be the only physical species that pretty much directs its own evolution.

We are not slaves of our physical makeup. For example, to use your terminology, we are not "designed" to survive cold weather. But we are capable of overcoming this limitation by dressing up. We are not "designed" to see well in the old age (well, many of us aren't), but we overcome this limitation by wearing glasses or contact lenses. We are not "designed" to communicate with people who are hundreds, perhaps thousands of miles/kilometers away from us, but we overcome this limitation with E2 and other forms of long distance communication. We are not "designed" to watch actors long dead perform, but we overcome that limitation by capturing their performance on film and video.

And, by the way, our teeth are not that sharp. Compare them to those of a wolf or a tiger. How well would we fare if actually had to bite the meat off a living cow?

As for digestion, why is it that after eating a hamburger, the human body has to take blood away from the brain and flood the digestive tract with it? And make us sleepy in the process. I have eaten many a vegetarian meal that does not have this effect.

We like what is good for us? Does that include alcohol? And don't forget all the cholesterol in that juicy hamburger of yours. Is that good for you?

If there is anything designed in this whole picture, it is that hamburger. Designed by humans for human consumption. The meat has been ground at first, then broiled or otherwise prepared. We can design anything we want to suit ourselves: Instead of caves, we live in houses. We cannot fly, so we build planes. We are not designed, we are the designers.

If there is any "design" in us, it is the ability to choose. If you choose to eat meat, then eat meat. If I choose to eat tofu, then I'll eat tofu. I don't tell you to relax. I hope for the same courtesy from you.