The best breakfast options is to have fruit and veggies smoothies that help you to have busy mornings. They are rich in proteins and the fiber content that are important to the body. But, as per the research, it is not the best practice workout before a meal. The reasons are they are quickly digested and often very rich in fiber that can results in stomach upset. Considered milk as a base and you could start to feel queasy as it creates some of the disturbances during workouts.