, I'm a runner. I currently run 21-28 miles/week and I did my first half marathon this past October. I highly recommend Brendan Brazier's books--check out his site, brendanbrazier.com
. He is a vegan triathlete with a heavy emphasis on foods geared towards expediting recovery.
You CAN be a runner/endurance athelete without eating meat/animal products... You just need the information and resources to do so. And it might not even have been a matter of protein--it could have been overall calories or some other unidentified issue. But definitely check out Brazier's site and books. His "Thrive in 30" video series--you can sign up for this at his site--is a great starting point.