Hello, Dr. B.
You don't mention the type of hotel you stay in, whether they have the mini fridge or a small kitchenette with microwave, or if your job takes you to hotels in the central area of a city near convenience stores, grocery, or health food stores, but here are two ways you might eat healthy on the road.
On arrival I would head to a health food store to stock up on items made that day, ready-made items such as boxed cold noodle salads with vegetables, wraps, or vegetarian or vegan items. Grocery stores and most health food stores have a hot food section for takeaway or eating in, and you can make your own smart food choices. Rotisserie chicken, soup of the day, vegetable salads, pastas, fresh fruit. In the drinks' section there are so many healthy drinks available now you aren't limited to sugary soft drinks. If you can find some good cheese, a good baguette, and fresh fruit, that can be a quick sustaining meal.
At home before travelling you could stock up on packaged meals found in any health food store, and pack them. I don't mean Spaghetti Os or mac and cheese in a cardboard cup variety. These packages come in a sort of foil pouch and the food inside is like a cooked stew that only needs heating up so you need access to a microwave. Pack an up breakable, microwaveable bowl or cup. These packages contain cooked lentils or other grain with vegetables, rice, eggplant, tofu, and are very filling. If you can pronounce all the ingredients, I'd say it's a safe bet. You can pack these and have a quick meal with protein, fiber, carb, vegetable. I just looked at a package that I have in my pantry and here are the ingredients: Water, lentils, green split peas, sunflower oil, tomato purée, onion, black pepper, ghee, salt, garlic, lemon juice, cardamom, green chili, coriander leaves, mixed spices, ginger. This one is called Dal, an Indian dish. There are all sorts of meals if you don't want too spicy. Zero sugar; four grams fiber on this package. Happy healthy travelling!