I don't understand the physiology perfectly, but from what I've read, it seems that on a higher-carb diet your body needs more water to process higher carb foods, so it holds onto what it needs. On low-carb eating, your body uses less water and gets rid of what it doesn't need. There are other factors, such as sodium that change the balance too. High-sodium, high-carb will hold on to the most water, and low-sodium, low-carb will get shed the most water. There are a lot of other factors too, so this is a bit of an oversimplification.
For me the difference is 8 to 10 lbs. During TOM, I try especially hard to eat lower carb than usual, not only to try to decrease TOM cravings/hunger, but to try to minimize TOM water weight gain (which sometimes works, sometimes doesn't).
It takes (for me) about 3 to 5 days to make the transition (either to gain those 8 to 10 lbs of water, or to lose them again).
Last edited by kaplods; 08-12-2010 at 09:54 AM.