Do you want to a) loose some weight then gain it right back? or b) do you want to be a healthy person?

a) crash diet and work your ass off for two weeks, get burned out, go right back to your previous shape

b) establish healthy, reasonable diet and exercise habits you will be able to stick with on a year round basis.
-start reading nutrition labels on food
-don't kill yourself every workout (you will burn out and stop working out)
-find healthy foods you enjoy eating. don't like grapefruit? try oranges or pineapple. don't like cauliflour? try brocoli or spinach
-treat yourself. been eating healthy all week? grab a beer and pizza.

cliffs notes: find a reasonable diet and excercise program that won't burn you out in two weeks.