I agree with bogusjourney-its about finding what works best for you.
I've gottten tired of the chronic cardio, low fat regimen, and I've gained weight eating to satisfaction with zc, high fat (while others have succeeded with this). Each person is different, and there's a bit of trial and error involved in finding the best way of eating.
That being said, we should be aiming for health. If you try eating fast food consistently, weight/calorie balance won'be be your biggest problem. (There's also energy level, immune system, mood to consider..)