Unlike the prior responses, I agree with you - that carbs aren't really good for ANY of us. Just because someone can eat carbs without gaining weight doesn't make carbs GOOD for them - there is a LOT to health and well-being beyond just the number on the scale.

That said, I don't have much helpful advice to offer. In my home, I cook the food, so my husband eats what I make. If he wants something else, he'd better learn to cook! Sometimes he wants junk, and I will buy it for him, but only with the agreement that he brings it to work and keeps it at his office - it is NOT allowed to sit in my kitchen. For the time being, I say just make normal meals and you just eat the met and veggies/salad - be a shining example, and I bet eventually they'll have no choice but to admit they can see that you are HEALTHIER and HAPPIER eating that way. It's much easier to lead by example since forcing someone to try to change something as deeply ingrained as lifelong dietary habits can be not only a battle, but could actually cause a pretty major rift.