So can cardio reduce your muscle mass?
It seems many people have told me that cardio can take away muscle mass. One reason is that if I do cardio after I workout, then I won't have any readily available energy left, so my body will start to metabolize the protein for energy.
However, the problem I find with this is that I've always learned that once you have used up all of your energy from carbohydrates, you would then start to metabolize lipids/fats. And it is not until you are done metabolizing your lipids until you move onto protein for energy.
So what is your take on this? Is there anyway for cardio to take away muscle mass or negate any gains I've made?