I don't give my horse any hard feed. He works reasonably hard, I ride him everyday and we do a mixture of dressage/school work, jumping and pole work, mini XC and lots of cantering round fields. I am on a misson this time of year to keep his weight down and allow him to be turned out overnight on our very good grazing without his muzzle. So far it's working, but if I don't keep up the exercise he will quickly put on weight and then need his grass restricted.
All horses are individuals. Ben's next door neighbour has 3 big hard feeds per day, and 2 huge nets full of haylage every night. He works about 4 days per week but is a different breed and has a different metabolism from mine.
If you need advice, your vet is the best person to advise.