Most do gain weight as they start their diuretics on MONDAY while still depleting then by Wednesday they have most of their water gone and between WEfDNESDAY and SATURDAY they eat 15-20lb of food WHICH HALF OF THAT THEY SHIT OUT, SO THAT LEAVES A 10LB SURPLUS IN WEIGHT, while only losing by this point another 3 to 5lb of water,
so 5-7lb is possible, 15lb hell no, not happening.
OTHERS LOSE WEIGHT as they drawer their water out late while they carb load, in this case you are right, they will end up lighter not heavier, and this way requires lasix, so it really depends on the approach.
I'm pretty sure Jay will be taking a loop diuretic. From what I've read, Aceto always restricts water as well. If Jay gains weight now it will just be food matter in the intestines. Otherwise he will have to increase water intake just before the stage (rehydrating).
Everyone I've seen compete while taking even just a potassium sparing diuretic and restricting water will lose weight during the carb up, even if going from say zero to 6-800 grams of carbs a day the last 2-3 days.
The idea with the carb load while water depleting is trying to increase the muscle glycogen which would in theory pull out a little more water out of the subcutaneous space into the muscle. But still, on the scale it's a drop in weight.
Of course, IMO, many look their absolute best the last day of depleting or after first 1-2 meals of carbs.
The 2 day show is tricky. Too long to stay very dehydrated. Will have to rehydrate after prejudging and pull water again for saturday.