I don't want you guys to beat me up on this but its common with highways in any part of India, you simply won't get the food which is worth drooling. You might get good food but that's just about it. Its even more serious in case of non-veg food. Obviously there are exceptions to this but on an average, lipsmacking food is available with in the confines of city. Whenever you are in Delhi, buzz me or send me a PM and either I'll take you to places serving good food or at least I can guide you to those places.
I have had fantastic food, but mostly on smaller shops, off the main highways. the typical large highway 'food courts' and larger dhabas have typically terrible food.