I teach kickboxing, 6 classes a week + my own training means carb control is critical.
Pizza/pasta have been my lifelong staples and now they're a deathtrap, so my solution is porridge oats (not sure what it is in the US).
I buy bags of different nuts, smash em up and sprinkle them in the bottom of the bowl, fill the bowl with oats and use semi-skimmed milk.
Microwave for 90 secs, let it rest a minute then another minute full belt, sprinkle sweetener on it and that will last me from about 8 am to 1 pm.
Low GI works a treat.
Another thought, instead of being a gym bunny for hours, research HIT training - 30 sec bursts - so hard you want to vomit (you might guess my mind set from the statement), short rest then do 2 more reps.