I have found a more vegan diet to be better, eating more raw and living foods, but I will eat lamb, poultry and fish as long as it's organic. I don't eat meats to often, but more fish all the time.
The thing is you really have to learn to listen to your body and see what it needs and give it that. A little meat sometimes is ok, as long as you can get free range healthy and organic, no hormones, or antibiotics used....
People with inflammation issues have to stay away from the red meats, bad for it...
There's a good saying going around ----> "Eat Living Food To Live, Eat Dead Food To Die"
There is just one problem for most people doing the vegan diet, they don't know how to do, and that is why most vegetarians look like they're dying.
Meat is a complete source of protein and balanced with many other things as well, so when you do vegan you need to MIX many different sources of vegetarian foods to make a complete source of proteins, etc...
The oldest living people live in the Baltic regions of the world, they live on diets high in cultured/soured cheeses, milks, kefer, and yogurts. This supplies them with the protein they need and friendly bacteria to help maintain a healthy digestive system.
REMEMBER one thing always, you need a HEALTHY gut/digestion, because without it, then you don't digest and assimilate food for productivity!
PEACE