The Broscience is strong in this thread lol.
But seriously, how fragile do you think the human body is? How could we have survived as a species if we just fall apart without food every hour or push the body without drinking some scientifically advanced super nutrient water or whatever other silly question we see on forums all the time.
At any one time our bodies have enough fuel to run several marathons. So stop majoring in the minors. Stop worrying about what happens at every minute in the body and pay more attention to what the body does over a span of a week or a month.
No, not eating for a few hours, which is fasting seemingly for lazy Americans, and then doing cardio will not turn you in to a skinny jeans wearing hippy. Maybe if you didn't eat for 24 hours then did several hours of cardiovascular and did that every day for a month you would, otherwise don't worry about it. You will be fine. The body is far more resilient than you know.