Stuffing

Stuffing on the weekends

So long as you don't starve yourself during the week I doubt you'll lose capacity for the weekends. In fact your biggest problem may be stretching your stomach after that binge and feeling hungrier than usual afterwards with your stretched out stomach during the week.

That said it sounds like you've already got good ideas, eating a regular meal and then bloating with water is a great way to increase your capacity without gaining weight or being weighed down with a ton of food for the next 24 hours.
4 years