I would be writhing in pain if I attempted to consume 3-5k calories in a sitting. I consume a lot of calories on basis that I also burn a lot cycling, but nowhere near that in a sitting. Even 5k/day for me would be painful.

I can consume 3k a day eating clean, but no more.

Eating all that in one meal would require some extremely unhealthy eating, for me.

I know sumo wrestlers and other extreme athletes are capable though.

3k-5k calories is 3 big burgers with fries, or two pizzas.

If GP is eating that much, they are very overweight. You don't burn that much calories during exercise, unless you are running a marathon (which I would not recommend doing 3 times a week).

3k-5k isn't a normal day, it's what happens during a binge. I would almost never do that after a workout, I would usually just writhe in pain from the hunger for the rest of the day. I rarely go over 2k calories during a normal day, but after a one hour workout, 2k calories doesn't even slow me down.

Interesting, thanks for following up and sorry for making assumptions. It seems we're all different. After a one hour workout I do get hungry, but not that hungry. I wonder if it's just different between people, or if the type of workout makes a difference -- I usually run or ride a bike at medium intensity, maybe it's different if you lift weights or do something more taxing?