I mostly ride bikes for exercise and need fuel at least every hour on a ride or else I will bonk out. My output is 500kcal/hour based on power meter, a 4 hour ride would be 2000kcal, it's not doable without some food intake.
I also love weightlifting while being fasted. One meal end of day for me has put me in the best shape I ever have in 36 years. So much that I actually took up running haha.
Then I could wake up, ride hard for hours (hilly terrain), and feel no need to eat until the afternoon.
I do IF and do most of my physical activity before my first meal every day. It was hard at first, but now it's when I have the most energy and clarity.