Assuming you're looking for a serious answer, I'd recommend eggs. Boiled eggs are quick and mess-less to cook, though you should limit yourself to just two a day (and perhaps only eat the yolk of one if you need to watch your cholesterol level). You can supplement this with fruit; apples and bananas are good if you want to take a bite out of something, or if you'd rather have finger food then blueberries and grapes work fine. If you'd rather not deal with anything too sweet in the morning, unsalted mixed nuts (you can get these at Costco) are a good morning snack too. As for beverages, a cup of milk should work fine. I personally have tea for that caffeine kick (I save my daily cup of milk for dinner), and coffee's not a terrible option either if you can stomach the taste.
OMM: o fuck, signatures are back
I don't have anything in my pictures folder except for shitposts, so this motivational image will have to suffice for now