Periods of vegetarianism are very helpful - diets should be cyclic. But if you study cultures that are vegetarian versus cultures that eat small amounts of animal products, the vegetarians die sooner.
Vegan parents have children with birth defects within the very first generation that meat eaters just don't have.
Naturally you can find studies that say vegetarian is bad, good, indifferent, it all depends on who's doing the study and what agenda they are trying to push and what exactly they look at. Mostly these short-term studies are showing that vegetarians are better off simply because they aren't eating the Standard American Diet full of processed foods. That's why I read up on cultures that have been around for centuries. Even Ayurvedic based vegetarian cultures have a life expectancy of about 60 years, while the Hunzas, a mountain people who drink goat's milk etc., live 100+ years. That's quite a huge difference.
Add to the that the difficulty of getting Vitamin B12 in a vegetarian diet, and how the lack is causing Alzheimer's, and that clinched it for me. I eat meat about once a week, usually as liver because muscle meats are not that nourishing, drink broth at least once a week, eat as many eggs as I want, fish and seafood occasionally, and now that I've studied up on RAW milk versus pasteurized, drink that too.
I got into a lot of trouble when I was a vegetarian, got very anemic etc. It's a heck of a lot of work to be a healthy vegetarian, you have to know your stuff to do it right. If you don't have juicer, aren't willing to ferment veggies and sprout grains, best not to go there.
No one should eat meat every day, it's just not necessary. But neither should you cut it out altogether. Balance is key.