Worst way to lose weight is by starving yourself. What you need to do is eat a healthy AND balanced diet combined with exercise.
For the diet, yes, you need carbohydrates and other fatty foods, they are necessary especially for someone at your age. Its when you eat too much of that that you start to store the extra fat. Use a site like fitday.com to get an accurate reading on what you are eating and what you need to change in your diet.
As for exercise, if you want to lose the gut what you need to do is run/jog or other similar cardio-exercising which get your heartbeat up and a sweat going. You could also try ab-crunches, but to work on your lower abdomen it would be best to use one of those benches where you can lock your legs near the top, then sit up and rotate your abdomen left and right repeatedly until it buuuuuurns!...