I definitely can eat enough food in 6 hours to turn myself into a human lard bucket after a relatively short period of time if I don't do anything to burn off the excess calories. But this is a very fun conversation and I do appreciate it greatly.
It is amusing how you use kilometers instead of miles to make it sound like your hikes were further. Then in almost the next sentence you tell us how you lost 35 pounds instead of 16 kilograms. 31 miles and 62 miles in a day is still a really long ways to walk. So why bother to mix in the metric system?
You burn about a hundred calories per mile walking. So your long walks burned 3100 calories to 6200 calories. When I have ridden between 100 miles to over 300 miles in a day on a bicycle at a moderate pace of 16 to 19 mph I was burning over 50 calories per mile which comes to 5000 to 15,000 calories. Oh and the majority of the pleasure that I received from riding super long distances was the joy that only comes from humiliating your half dead friends by bouncing out of the saddle and catching the slip stream of a slow semi going up a hill and leaving them behind after 250 miles.
There are about 3500 calories in a pound of human fat. Unfortunately, it is not possible for anyone I know to metabolize fat alone at a high enough rate to keep up a good pace on a bicycle so you have to eat a lot of food along the way and drink a lot of water. However if your butt hasn't been turned to leather from the tens of thousands of miles of previous rides you probably would not be able to make it much past a hundred miles without being in a lot of pain anyway. So most people will never be able to experience this form of ecstasy.
But trudging along all day on a horrendously long walk without eating is very possible and I salute you for it if that is what you did.
Intermittent fasting. Look it up. Also, I’m an American living abroad. The hikes are in meters. I’m not going to change them for you. Just do the math. 1km = .625 or 5/8 of a mile, which is 5,280 feet.