But do you do cardio on an empty stomach before breakfast?
I know a lot of guys do this and swear by it, but I never, ever do or did, I just didn't think it was a good idea to do something potentially catabolic after not having eaten for 8 or so hours, I eat normally every 2 hrs to avoid this exact type of situation .
That being said ...IF I was to do it. I’d do very low intensity stuff like walking for an 45 min. and do the high intensity stuff later in the day. And I'd definitely have a good dose of BCAA before with perhaps some glutamine just to protect my muscle.
I think it's actually much more important to know how many calories you take in each day and if you're in a small deficient at the end of that day on a consistent basis.