 Some people can’t work out with a lot of food in their stomach, some can like myself. I usually eat a cup of oats with peanut butter, and then I’ll usually have some type of simple carb, usually fruit, sometimes sugary cereal. I also work out in the mornings and one of the most important things I make sure i do is hydrate enough. Since you just woke up, your body is dehydrated somewhat, so make sure you drink a lot of water as soon as you wake up.