As you say things like complex carbs are probably a good thing to avoid, so if he is ordering room service to choose the salad on the side instead of chips or rice. He could also ask for meats to be grilled, not fried, in a hotel situation and usually they are happy to comply. If he is longing for pasta then he could choose a tomato sauce instead of a creamy one to save some fats and try to get into the habit of not eating the entire plateful as often it is the portions that are the killer. And if he can, have plenty of fruit on hand for snacks. Lots of water to drink will keep him hydrated and less likely to snack too.