How can a 16-year-old lose weight if you weigh 215 and are 5'10'' and want to lose 15 pounds off your stomach but you don't drink sodas and you watch what you eat and work out and stay active?

Start an aerobic workout regimen along with strength training. Mixed it up with running, biking, rollerblading, and/or swimming to keep from getting bored. Unfortunately you cannot target specific areas on your body to lose fat. Your body just doesn't work that way. You can do all the ab work in the world and if your diet is poor your abs will never see the light of day. I mention strength training because muscle burns calories. Consulting with a health care provider will help you discover other benefits of strength training. Stay hydrated - drink lots of water! It's good for your complexion.