I've always been the cook in my relationships, and I've dated somewhat picky guys, to the pickiest guys, and I've got to say when it comes to making a recipe either healthier or more unhealthy, it all comes down to ingredients.
In the past I've taken a standard lasagna recipe and substituted organic and low or nonfat dairy products, and left out all the meats and replaced them with a layer of 'italianized hummus' of my own creation(w/ basil, thyme, cooked shelled lentils, and tahini), and/or layers of fresh vegetables and herbs. Sure the sauce may have had a few calories, but if you make your sauces at home; which is as easy as boiling pasta, than you can make them as healthy and full of vitamins, minerals and fiber as you want ;)
But what it really comes down to is knowing what the bad ingredients are in a recipe, and knowing what good ingredients could easily substituted. It may take some more money or time, but it's well worth it when you're eating a bowl of macaroni and cheese and you're guilty for not feeling guilty about eating your comfort food, on a cheat day.