I would think so. You'll want to make sure you're getting enough primal carbs to meet your needs - squash, sweet potatoes, etc. I ran the Chicago Marathon last year and the Army 10 miler after starting PB. I caved at the last minute to the "I need pasta to get my carbs!" mindset and really wish I hadn't. I had a lot of trouble with stomach cramps and such. Since you've put in the miles, you'll be set - good luck!