There are a couple of points to make here.
First, you don’t have to do your cardio on an empty stomach in the morning in order to lose fat. You can lose fat just as well by exercising at other times of the day.
Second, if you do choose to do cardio on an empty stomach, you do not have to worry about your muscles shriveling up to nothing.
If you want to do your cardio (intervals preferred of course) first thing in the morning, go ahead. But don’t expect any magical results that you can’t get from training at another time of the day.
I prefer that people follow a consistent approach, performing strength training followed by interval training – at any time of the day…it doesn’t matter. Heck, you never have to do slow, boring cardio ever again if you eat right and train consistently.
Strength and interval training takes less than an hour and I guarantee you’ll get the same or better results than doing your cardio in the morning and weights later in the day. It doesn’t seem to matter what time of day your strength and interval workout is done – it will always get you results.
And do you have to eat before exercise? You don’t have to, but keep something close by in case you get light-headed. Otherwise, if you just can’t eat anything before your AM workout, don’t worry about it, you’re probably not going to lose any muscle.
The Bottom Line
As a society, we tend to look for tips and tricks that make things easier. Nothing wrong with that, but there is something wrong when others exploit this desire with false promises.