Get out and run, swim, play sports when you can.Eating healthy is the hardest part for me XP but try to get fruits and vegetables into your diet a lot!
Cut back on things like ice cream, soda, chips, or any other sugary/greasy foods.Diet sodas are perfectly alright.
Llimit yourself to about one a day.Don't eat LESS! eat HEALTHIER! eating less will actually make you fatter, but don't eat TOO MUCH either!!!
Besides, unless your OBESE I don't think you should worry about your weight your body's still growing things could change.