rules i have for myself as someone who works a demanding job while heavily restricting:
always have a snack in your bag for emergencies, like if you get suddenly dizzy or nauseous. best if its something like crackers or pretzels that you can pick on and put back that doesnt make a mess. better yet if its something you don't like all that much so you wont want to eat it.
similarly, always have some pain meds for headaches, body aches, etc. we dont need to suffer needlessly.
dont feel bad for needing a low cal energy drink. 10 cals will not make a difference in the long run :)
never accept food from work. this is more applicable to me bc i work childcare and I feed them snack and lunch and it can get so tempting watching them eat while very hungry, but if you need to eat you eat your emergency food. nothing else.
always have a full ice water bottle. no excuses.
feeling sick and fatigued as a result of restricting is not an excuse for me to call off work. I need to build a tolerance for this if i hope to keep making progress.