Hi Slimslow,
As everyone else says, you DEFINATELY need to eat more - not only to give your metabolism a good kick into working again, but at that tiny amount of calories, theres nothing for the Xenical to work on. Are you seeing a nurse whilst on this? Maybe they could give you a few pointers.
I would definately up my calorie intake and even if your not used to eating lots try and have 3 to 5 smaller meals throughout the day. This doesnt have to be massive platefuls either, a couple of boiled eggs and oatcakes, small can of soup, tin of tuna with some kidney beans etc. Quick things that you could have during the day instead of a larger meal all at once.
I completely understand where you are coming from, I have 3 kids myself and running about after them I used to forget to eat until 3 or 4 in the afternoon when I would be completely ravenous and stuff my face till I was ill.
I have definately noticed a difference in my moods, tolerance and energy since spreading my meals out better. It might help to keep a food diary on here, we all just want to help each other here, as we are all going through, or have been through the same
All the best
x