This sounds easier said than done in some cases..
We are lucky our little one eats whatever I put infront of her. In saying that though, she was only 7 months of age at the time of booking the holiday. I still needed to brace her for the huge cultural change. In particular, in Asia they cook with alot of peanut oil and add egg nearly to everything. The last thing you want is an allergic reaction in a foreign country. Unless you plan on making every meal yourself- which isn't always possible when you're on the go, or you will be giving bubs jar food, try and cook food similar to that of what you may be eating over there before you go so when you eat out over there it wont be so foreign to her/him.
For me, I needed to be assured that she had no allergies to nuts or egg. I would also give her fish, rice and all the fruit I could get hold of. If your bubs protests to the country's local cuisine, then perhaps its best to go to plan B, of either jar food or perhaps taking non perishable food with you (you will need to check customs if the item is allowed into the country).
I had been exclusively breastfeeding bubs for 7 months, but before we left I tried her on a couple of brands of formula for that "just in case" factor. And to be honest it was a lifesaver a few times when we were caught out and about, particulary on the plane, where I found it a bit tricky breastfeeding in such a confined area.
I also introduced a dummy to her before we left. I was dead agaisnt dummies, but for travel its a must. Not only for some quiet time in the hotel room, but it is essential for babies to suck on something in take off and landing on a plane. The sucking action helps their ears adjust to the altitude and cabin pressure. I would just pop it it during descent and take off. While other babies on board were screaming, ours just happily sat there sucking on her dummy. You could also let bubs have a bottle or breast, but this isn't always conveinent for busy airline staff to constantly warm up bottles, or feed in a confined space.
We took her to our doctor for a general checkup, made sure she was up to date with all her immunisations and asked if there was anything else we needed to prepare her for the region we were going into, such as insect repellant and what to do incase of diarrhea. It's also a good idea to refresh on your First Aid course for babies.
As a general rule for the whole family always carry a First Aid Kit in your luggage that includes tablets for Diarrhea (check for babies under 12 months) heartburn and indigestion, childrens & adult pain relief. Never drink the water from the tap. It doesn't matter if you are travelling to a village in China or going to a 5 Star hotel in New Zealand, every country has bugs in the water that you and certainly your baby will not be used to. Either use certified drinking water or boil water and let cool.
If you have your baby on a strict sleep, eat and play routine like ours- you may be a bit worried that they will start waking up at 4am for breakfast. Believe me it happens and there isn't much you can do for the first couple of days. I found that if I kept a watch on me with our home time zone, I could predict feed and sleep times. It makes the transition a bit easier. Your baby will adjust as they soon realise when the sun comes up and goes down. Try to go with the flow and not force bubs into a routine in a different time zone for a short period of tome. You will just stress yourself and buby and you wont have a good holiday. Its only for the duration of the holiday anyway- be that strict headmaster again when you get home!