Question: Fasted cardio...worth it? If your schedule permitted and your main goal at the time was fat loss, would you do some of your prowler work/hill sprints in the morning on an empty stomach? Answer: I think it's a nice gimmick - if you are so fat and awful that you need to resort to that to make you burn fat, you might want to reassess your training. Having said that, training in the morning is a necessity for a lot of people and I couldn't do hill sprints or Prowler work with food in my stomach. THUS - it would be fasted but not because of the Fat Guru Voodoo that they do. People don't lose fat because they do fasted cardio - they do it because they are dedicated enough to wake up every morning and do something. If they do that, chances are they are making other life decisions that are healthy. Like the study that says people who drink 2 or more cups of green tea/day are less likely to get cancer or heart disease. If you are drinking green tea twice/day, you probably aren't the kind of person that eats a pound of Sausalito's and Bugle's at every meal. So in short - run when you can. If that be when the sun is rising so be it. At the end of the day, or more precisely the end of a lifetime, what matters is the total work you put in, not what time you do it. At some point, I hope that people use more common sense in regards to training than trying to turn to gimmicks for the answer.