Gaining

Yes.

After a bikini or bodybuilding show, those competitors have been in a torturous caloric deficit for so many months, they often feast out of their minds for the next couple days and it's not uncommon for them to put on 15-20lbs in a few days. There's a video of Kai Green eating an entire cake in one sitting as "the appetizer" to his celebration meal the day after the Olympia.

Then again, they're at such a low body fat%, even 15lbs they have shredded abs...

I think age and obviously metabolism have a lot to do with ones gaining. I'm old, male and an occasional binger. I over ate for two meals this past weekend. I gained two and half pounds when I weighted myself this morning. I have gained five pounds in three days of overeating last summer and got up to 230 lbs. I'm at 225 lbs. today.
It can pile on very quickly for both male and female, but being old (60+) really helps.