Case study of one, but I've been a (lacto-ovo) vegetarian for roughly eight years now. I do eat a lot of pasta and cheese (because I find it delicious). I've always had a high metabolism, and I actually have trouble gaining weight. I've always been under the impression that there is not one universal diet for everybody. Instead, people should choose something that works for them. This is what works for me, and I'm pretty dang happy with it, so I've stuck with it.