I had a HS friend who was a serious swimmer (not quite Olympic level but he won state championships) and watching him eat was insane. He would eat about 3x of what we all ate. Like literally down 3 sandwiches while we had one. I think he was on a 6000 calorie a day diet. I believe the potato thing. It sure sits outside what I think I could eat, but having seen others do similar, it seems realistic.

I do weightlifting and have gone through times where I do more weightlifting and less. The body just absorbs food when you do more work. Can't tell you the mechanics but it's way easier for me to digest more food when I do more weightlifting.

About 6 weeks into a cross country bike tour, I spent a rest day eating all day. I think I ate 4 massive burgers and a large supreme pizza. Probably somewhere around 6000 calories.

A week prior, I ran out of food in the mountains. I finally got to a store, bought a loaf of bread, a pack of Oscar-Meyer bologna, a pack of cheese slices, two sodas, and a red bull. When I left the bench near the store, I had a few slices of bread left.

When you put out incredible amounts of energy, you can eat a fairly incredible amount of food. I don't understand where the food goes, it really doesn't feel like you should be able to eat that much volume but you can.