You really ought to have it - make an effort not to miss it if possible (perhaps have it before putting babe to bed?). Very low cal diets are only safe because they guarantee that you get the right amount of vitamins and minerals - and if you miss shakes etc then your health will suffer. It shouldn't cause a problem if it is a rare event, but if it becomes frequent then you will be affected by it - you could start losing muscle mass rather than fat.
However I do think going to sleep early stops hunger!!