It is helpful and beneficial that you consume both of them, drinking a carb and protein shake. However, the natural source of protein and carb foods are a lot better since they do not contain artificial and chemically processed substances that may damage your internal cells. Before working out, you must consume much of a calorie food so as to give you energy in doing your workout routines. And you also need to consume protein foods so as to build up some muscles or even a great deal of them. A great deal of muscles in your body means you are able to burn more body fat if you focus on your exercise routines. Always remember that eating less of a calorie foods before working out is totally not advisable because you will feel tired, hungry and get exhausted and you won't have enough energy to perform your exercise. Calorie means energy to your body you need it to perform your workout routines. Don't just believe on other people who say it is better to consume less of a calorie before workout. They are totally wrong.