The above two obviously have experience. For me sadly it's about budgeting. I eat mostly organic veggies and fruits. I definitely feel the difference especially when I'm flushing out my system. Mentally, it could be a placebo effect, but I really feel a lot sharper when I eat Kale and tons of fruits for breakfast. It should be an add on. I try to stay away from red meats and focus on poultry and fish.
The Paleo diet is one step further. I believe that humans were meant to be vegetarians based on our anatomical structure. If you look at Gorillas look at how big they are and what do they eat. Besides insects, mostly plants and fruits. Yet they're as strong as 10 men. Also unlike carnivorous animals our jaws don't unhinge and we don't have fangs/canines at least not anymore. I'm not sure if I can ever go full out vegetarian, but I have considered it.
Treat your body well.
from what i read they eat meat too I could be wrong but not a whole lot
"The fat man flies at midnight"