I Need to lose weight, what do you guyz think about...?

the south beach diet? I know your going to say "Its not going to work and you need to eat healthy" I know i will,, but to start me off i need to lose a go amount of weight . South Beach diet? thumbs up or down? Oh and All Bran diet? Just for a week. thanks ..please u gotta help! Im 13 and weigh like 143! =(