Waking up and training in a fasted state is still very popular approach for people seeking weight loss. It is still believed that performing aerobic exercise on an empty stomach forces the body to burn more fat as an energy source.
Lets make this short and sweet:
During the exercise period, yes you will burn more body fat. However, over the 24-hour period the results are negligible, unless you are training for a very long period of time. Training in a fasted state also increases the breakdown of muscle protein. If weight loss is your goal, decreased muscle mass is the last thing you want.
In a previous post I mentioned high intensity interval training (HIIT) is more effective for fat loss and more efficient at preserving muscle mass. Have you ever tried to perform HIIT on an empty stomach? All we will say is: good luck.
Fasted cardio may have its place for the experienced athlete, but why put yourself through the pain of training on an empty stomach? Consume a nutritious meal and get your mind and body in the right shape to burn fat.