If you're looking to gain mass and have a good carbohydrate tolerance, place a bowl of fiber-rich, low-GI rolled oats along with half scoop of vanilla protein powder,  frozen mixed berries, pineapple and a small quantity of mixed nuts right next to your omelet.  This is a muscle building breakfast that’s hard to beat.   I place this bowl right next to my omelet for a breakfast that's hard to beat.