When I was multiday camping and bicycle touring over mountainous terrain, I tried skipping breakfast once (it takes extra time), and it left me strikingly weak.
I had a similar experience when I was a bicycle-riding missionary in Japan. I unwittingly reduced my calorie count drastically one day by switching up my breakfast menu and had to return and refuel early. At the time we were riding about 60-80km a day.
I had the exact same experience. I was totally outmatched. Interestingly though, in my typical life as a guy with an office job, I average about 1 breakfast per month and have no problems with energy in the morning.
Very different energy demands from office work.