I just read an article on boosting metabolism. Here are some hints:
*make sure you eat enough! If you go below 1200 calories a day, your system slows down & thinks it's starving & holds on to every calorie.
*avoid sugar & processed foods & load up on good foods like lean protein (fish, turkey, yogurt), good carbs (whole grains, fruit, veggies), good fats (nuts, seeds, avocados).
* get enough sleep (6-8 hours).
*do muscle building exercises. Muscle burns hotter than other tissue.
*try green tea. The caffeine will speed your metabolism but it's also good for you unlike coffee or coke.
Good luck!