Vegetarian diet is excellent. And adding meat occasionally isn't the problem. It's all the soda, breads, pastries, pasta, cake, candy, processed foods that do it.
And as far as the unhealthy living longer - not so. I was a heavy smoker when I got cancer. I quit smoking and I'm now cancer free for 5+ years. I was also a majorly heavy drinker. Having a drink or 2 a day is good for you. I was in the "unhealthy" range. I could drink a liter of vodka and I wasn't drunk.
People often get cancer due to genetics, or exposure to carcinogenic chemicals. It's better to enjoy life by trying to be healthy, than to just go with the flow and do as you please - suffering a painful death. No way am I going down without a fight. Having cancer made me think this way.
No, I know living unhealthy isn't good in any way (except if you enjoy it, then it's good in one way). I meant more as in the pople in my surroundings: those who live healthy seem to be the ones who get terminal or serious diseases while the unhealthy get their dosage of luck and duck some major bullets. Personally, I've got quite a few diseases and disorders, some could be terminal, but I've been anything but healthy (drugs, alcohol, OD's and so on), so I suppose I've gotten what I "deserve" (no, I deserve a good life, but I'm jokingly bitter since I was born with those things and not a result of an unhealthy lifestyle).
Still, diabetes is scary. I've got it in the family as well.