Are you talking about going no a diet for let's say a month to loose weight?
I would never go on a diet. I don't feel like restricting myself.
I do however eat very healthy everyday and darnit, when I want the cookie I eat it, just not everyday.

Let my wrap it up:
Going on a diet can help shed pounds, but a) is it fat you're shedding or water? b) diets won't give you muscles. That's a big argument for me, because muscles burn more calories even when your not working out.
I'll have a cookie now.