You can still cut calories, and eat all junk and fast food, and still lose weight. A calorie is just a calorie when it comes to weight loss. Obviously eating proteins, fibers, etc are better for you and keep you fuller longer, but if you cut 500 calories a day from your maintenence, then yes, you will lose. Even if you eat nothing but Twinkies all day. Of course you will be starving and not getting all the proper nutrients, but yes you will lose weight. Don't over complicate it.