Any vegans here?

I had a doctor a few years ago, tell me about the downfalls of being a vegan. He said the human body was designed to be a carnivore, and how certain vegetation really messed up your system. He had several charts on the subject, and made a lot of sense. According to him, the healthiest people on the face of the earth, with the lowest rate of cancer, heart disease, and diabetes, are the Eskimo. They have very little vegetation, and survive mostly on meat with a high fat content.