If he maintains alright on whatever you are feeding him and he is healthy then it has nothing to do with feed and all to do with training. Sure, you could feed a horse a bunch of feeds equivalent to a bag of candy, and yes, you'll get that sugar rush out of them, but don't mistake that for being forward because that will only come from correct training and correct aids.
If he's healthy and happy on whatever you have him on then just stick with that and focus on getting him to move off your leg more quickly during the ride.
We are not human beings having a spiritual experience. We are spiritual beings having a human experience. -Pierre Teilhard de Chardin