I've dealt with this issue several times when Mikey goes on his hunger strikes and am even dealing with it currently ohmygod_smile (we just moved to a new place yesterday and he doesn't eat when he's stressed). As BJ said, if you're not going to be around to monitor him, you want to give a much lower dose, probably half his regular dose.
If you are going to be around to monitor, then give a slightly reduced dose. For example, Mikey's regular dose right now is 1.5 so I gave him 1u yesterday morning before I moved him and Henry to the new place. He maintained that pretty well so I gave him another 1u last night without him going too low. This morning, I nudged it up a bit to 1.25u since his numbers weren't very good on the 1u but am now having to monitor him because he's at 43. :YMSIGH: Tonight, I'll probably give him a fat 1u if he's still not eating right, although I did just convince him to eat some FF gravy food, so at least I'm not going to have to force-feed him today, even if it does cause him to run higher tonight and tomorrow.