Gaining

It’s probably doable for a day or two, but I really doubt it’s sustainable for a month. Not to mention, your body is probably only absorbing a portion of those calories. After a certain amount you start to hit diminishing returns.

I can't imagine how that'd be fun after awhile. Seems kind of....mechanical.

It's doable. For how long...I guess it get easier as you keep doing it.

Did the body can adjust to such amount of calories, how can you do it on regular basis, I mean it's must be very hard in the beginning.