I have IBS (or so my doctor and councelor tell me, although I've never been tested for anything else or examined), and I've had some wierd appetite changes for about the last four or five months. Usually I get full very easily, so I don't really eat a lot. However, about once a month, (no correlation with my menstral cycle), I have stages where I am hungry all the time. It generally lasts for about a week. I will eat breakfast, then be starving to death by lunch.