Personally, I think that any "diet" that works for you is okay. I am trying to lose weight, but also get healthy and motivated, so I can't do anything like only eat grapefruit and cabbage. I am trying to change my "lifestyle"--meaning stay away from sugar and carbs as much as possible...not saying "never" to them, just rarely.
I thought the GI diet might work for me, and I have been researching it. In the end, I think I'll take what I learn from it and put it with some other things I know and do my own thing.
It's all about not letting the food get in my mouth. And, when it does, exercising (which I hate).