As far as I can tell the study doesn't even look at muscle or lean mass; so why are you saying there's no muscle loss?Who cares about what you think happens to cortisol levels? So cortisol goes up some (when its already at its daily peak) for the half hour or hour of fasted cardio, then you eat and cortisol goes down. If more fat is lost, more fat is lost. That's what this study showed, not more muscle lost.