Grains are a touchy issue. They aren't "needed" per se, but I like to do mine a la Stephan Guyenet and really eat the whole grain - not "whole grain" bread/pasta/products (what complete crap). Since I train heavy, they work great as glycogen replenishers and keep next day soreness to a minimum. So I would say they are useful for such purposes. I typically do either rice or quinoa.
1) eat real food - more vegetables, moderate meat, moderate fruits, less grains, less sugar, less vegetable oils.
2) exercise - moderate intensity cardio, sprinting, heavy lifting, dedicated stretching and mobility.
3) live - relax, de-stress, meditate.
Disclaimer: I'm not professionally qualified to make any formal recommendations. I've just done my homework and I'm my own guinea pig. All of my data, unless otherwise cited, comes from a sample size of n=1 (me).