It's true, because instant rice has been pre-cooked and then dehydrated, its chemistry is inevitably altered. It's like vegetables...the more you cook it, the more nutrients it loses. Most instant rice is fortified with nutrients added back in, but it's not the same.
Brown rice is more nutritious than white rice, but many people don't like the taste/texture of brown rice. (I've found that it grows on you after a while) This is how I see it: Brown rice>> White rice >> Big Mac. Of course, that might be because I'm used to using my Nutrition Degree to help people use diet to lose weight (and eat healthier). For most of the people I deal with, rice (any kind) would be a big step