While a good balanced diet are very important, that's not all of the equation.
Personally, for my horse Red, he is on pasture 24/7. Yes, he carries around an extra pound or two because of it, but I feel the action of grazing all day is the best way to keep his body healthy (especially circulation and digestive system). He gets exercised almost every day and is in good shape.
He gets fed a small amount of Purina Omolene 200. Basically just enough so that I have something to mix with his Platinum Performance CJ supplement. While feed-throughs aren't the best way to absorb joint nutrients, I do like feeding it anyway for it's other ingredients.
He also gets Previcoxx once a day to manage some of the problems he has.
He gets Adequan once a month.
He has a 2 degree wedge pad under his front shoes, and regular shoes on the back (for traction).
Every horse is different and will have different needs. It is important that you consult with your vet to figure out what is best for your horse.
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.