I don't know that much about cleanses but it seems to me that it would be better to eat "clean" food more of the time to avoid having to "clean" out bad food.

Avoiding processed food, sugar and a lot of saturated fat will probably make you feel better if you can stick to that kind of diet for one week. It is difficult to avoid ALL of these things but if you were to use the will power to fast to just eat clean, healthy food for a week, you will gain much more quality nutrition and will feel just as good.

That is only a statement of opinion though.... I am not a nutritionist!