I exercise on an empty stomach for most runs. I wake up at 5, have a cup of coffee, drink some water, use the Theragun on my legs, and then start my run ~5:45. If I’m going 10+ miles, I’ll have a pop-tart or two pieces of toast. If I’m going 15+ miles, I’ll put some peanut butter on the toast or oatmeal and bring chews along. Simple carbs that get digested quickly and won’t leave me feeling heavy. Since I eat enough during the day, most of the time there simply is no need to supplement for running.