Which is better?

Doesn't matter. I don't eat breakfast, only coffee with creamer. Suits me just fine.

It's a matter of personal preference. If you're eating a well balanced diet chances are that you wake up with enough stored glycogen to get you through 60 to 90 minutes of moderate exercise without bonking.

I'll typically run on an empty stomach (need my coffee first though..) with the exception of my longer runs in the later stages of a training plan (90 minutes or more) I'll eat something light a couple of hours before heading out the door.

Completely up to you. What you are doing for exercise might have an impact, too. This time of year I run 3-4 miles before work every other day. I get up, put on my running stuff and head out the door. I get home, shower and don't usually eat my breakfast until around 10am and that's just a protein bar. If, however, this were winter and race season was in swing, I'd be running 8 miles or more and I'd need to eat something a half hour or more before I started and probably something sugary during.

Generally speaking, a workout of less than 90 minutes or so you can do on an empty stomach or right after eating, whichever is comfortable. A longer workout will require food intake at some point so you have enough energy to get through the whole thing.

singletrackmtbr wrote: »

What about both?

This is me.
I do HIIT in a fasted state, then go for a walk or swim.
A few hours after breakfast, I lift weights. I see value in both, and it's a personal decision.
A personal trainer told me cardio in a fasted state burns more fat, but no definitive science is available to prove this.
It seems to work for me, but my fat loss could be from other items in my overall fitness program.
Who knows?

Personal preference.