What sort of vacation are you going on that doesn't involve walking every day? What will make it impossible to "eat right"?
Who is in charge of your activities?
Who is in charge of the food?
I recently went away for a few days with my dad and sister and her kids. We stayed in an inn (no fridge in my room) and spent the days at my dad's cabin. I planned ahead by having grapes, small rolls, hard cheese and juice in my inn room so I could have breakfast before we headed to my dad's around 10am. I also took a little walk around the town in the mornings.
At my dad's he would make bacon or eggs or something and I'd have a little bit of egg and maybe a bite of bacon. Then we'd work in the yard all day.
We had some restaurant meals. I had a steak sandwich, and took half of it home. I had beer and wine, in moderation since I was the driver back and forth to the inn.
We went to the city one day and walked all around (my fit bit was very happy that day) again I made sure to have plenty of water and we sort of grazed at different spots along the way, then had lobsters and steamers for dinner!
Yes, there were lots of things to eat around me, but I was still in control of what went in my mouth.
I did come home with some water weight from the long driving (and a tick bite that gave me lyme
) but other than that it was pretty much within my control.
Hopefully you can have enough say over what you do on your vacation that you enjoy it and don't feel like you've lost control of your choices.