Whats a good little diet for a 14 year old?

Well, i am 14 year's old and over weight by thirty pound's. I am starting p90x in two week's and begging my FULL diet and exercise then. For these two week's what can i do to drop like couple pound's any thing special. I know not to drink and soda, chips, candy etc...... Any suggestion's that you would like to tell me, thank you for the time for reading this post.