Rice bran isn't sugary. I forget the carb counts on it but I feed it to get some fat into my pony who is 37 and has some sugar issues. I feed her a ration balancer, the rice bran(just a bit, because she is fat and small), some very low carb hay stretcher. Hay is free choice for now, my winters are very cold. If I go subzero I also make a warm beetpulp mash with some timothy pellets.
I have 2 others who get the same diet in slightly varying amounts. An older app, large pony mare who was cresty but looks pretty good now and a TWH mare in her early teens who was a skeletal wreck when I got her. The TWH gets more rice bran in her dish. I was giving her senior feed but it was making her hot which tells me she was getting way more sugar than she really needed from the senior.
I would probably use more beet pulp except for the fact that it's a hike down hill to the barn from the house and it gets real icy. The bucket of beetpulp is heavy and I've fallen hard out there too many times. Nobody will get fed if I'm dead.
I also have no way to effectively separate the 3 mares at mealtime. I have to stand guard to keep the old pony out of the TWH mare's feed. Gets brutally cold out there at times and if I abandon ship the still alpha pony mare finds nothing but hay stretcher left in the TWH's dish. I only have to tough it out for 15 minutes or so for the TWH to finish the extras. I suppose I could tie the pony for a little bit until the others finish and it may come to that but it seems like being a crabby and bossy old bat keeps her going.