I run every morning at 5:30 and definitely on an empty stomach. I have had 0 problems doing this. I have a super quick shower (5minutes) afterwards and then I eat a very good breakfast. The few times I have eaten and then tried cardio, it just doesn't work out for me. I feel sluggish and slow and unmotivated. If I had to eat something before the workout, I would probably choose 10-15 raw almonds.

I think it is really important to do what works best for you. You will hear differing opinions about different topics. In the end, if your system is working than keep it up!

BTW--everything I have read indicates going into "starvation mode" takes much, much longer than just a night's sleep.

I get up at 5 and run about 5:20 (or do yoga). I often go on an empty stomach, or I have a small easy to eat fruit (1/2 banana, small orange, some grapes) or maybe 1/2c of a green fruit/veggie drink. I can't really say I see a difference on days I do eat something vs when I don't. There might be a difference, but it would take some careful evaluating to tell But I feel good about at least putting a little something into my system - but there's no way I could eat more and not get sick or uncomfortable.

I agree, especially in an early morning routine and you aren't working out for several hours on an empty stomach, it's only an hour. I never ate when I worked out that early, just no time anyways...