during my bp comp days I'd easily make the 65's from a buck 70 just not eating breakkie and drinking strong black coffee to make myself take a good dump, so that's 5 pounds lost just from not eating breakkie and taking a big dump
once I lost my 12 pounds by taking a double dose laxative the night before weigh in, and one more dose the morning of, and I didn't eat or drink anything til weigh in at 6 pm the night before the meet this was only through shitting with the laxatives and no food or water til 6 pm, I used no diuretics or did no sweating for this 12 pound loss
after weigh in I gouged on junk food and Gatorade and weighed in 3 pounds heavier than when I started, so I gained back 15 fucking pounds, so all of the gain/loss was water and "food in the gut/intestines"
so just like van the man said "it's water and what's in your gut"