I don't weigh myself the day after a big ride or tour anymore, because it is disheartening to see I actually gained a couple of pounds. I attribute it to water retention but who knows. I will check my weight a couple of days later because, happily, I have usually dropped 2-4 lbs from my pre-ride weight. I read somewhere that after big exertions, your body's metabolism is higher for several days after. So, my theory is that the my body keeps burning through the fat stores for a few days and that's why, even though I eat the same, the loss shows up later.

Disclaimer: I am not a scientist or nutritionist nor do I claim to be either! How's that for grammar?