The biggest tip I can give you is to be prepared. Preparation is key to being successful with your diet while on the go. Last year I purchased the Core150 StackPack - a bag that is designed for fitness people on the go - which holds a shaker, 4 core150 storage compartments, two meal pods, a laptop and documents. I took this with me to London this weekend, and I stored all of my supplements that I would need, as well as a couple of meals and my laptop and work files. As I am staying at my apartment I know what food I will be eating, but if you stay in a hotel, then do some research about the hotel - find out their menu, how easy it is to get a microwave put in your room, if there is a fridge in your room, and so on. By doing this, you'll be able to take a certain amount of prepared meals with you and store them in your room. You can then buy certain meals meals/snacks and heat them in your microwave and store foods and drinks in the fridge. Some hotels are easier to work with than others.
Even with my StackPack, I can't carry an endless supply of supplements. For weekends away it's perfect, but if you are traveling for a week or two (or more) then taking your own protein powders/oats/mass gainer, wouldn't make sense as it would take up some of your luggage limit (if flying). If you're driving somewhere then you can take your own. If you're flying then it's probably best to buy some the other end. Pills and capsules are small and lightweight, so you'll be able to take what you need.
Going away unprepared can easily throw you off your diet. If you're used to having good quality nutrition and regular supplements, then by not being prepared while you're away, your body won't get what it's used to. If you only travel once a year then it won't be a problem, but if you travel regularly then it will.
If you travel a lot, or are going to travel soon, then be smart and use the above tips.
Lee Gregory Fitness