Although the latest miracle weight-loss product on late-night TV might seem seductive, the pounds you'll lose aren't likely to stay gone. Strict diets are difficult to sustain long-term, and exercise machines are unlikely to make you look like the fitness models in the commercials. Fifteen pounds isn't a lot to lose, but if you want to keep it off, you'll have better odds making long-term lifestyle changes such as eating healthier foods and exercising regularly.
Incorporate exercise into your daily life and make it a priority. Schedule it like you schedule the rest of your activities, and try to do it at the same time each day. According to the Centers for Disease Control and Prevention, adults need 150 minutes of moderate-intensity cardiovascular exercise each week.
Add strength training to your workout at least two days a week, and cover all the major muscle groups between the two workouts. Muscle burns more calories than fat, so the more muscle you have, the greater your metabolism -- even when you're not working out. Lift weights, do a circuit-training class at the gym or try yoga, which uses your body weight for resistance.
Replace processed foods with whole foods. Eat as many vegetables as you like, especially leafy greens such as kale and spinach. Have fruit for dessert, and replace white flour with whole-grain varieties. The fewer ingredients your food contains, the better it is for you -- if you can't pronounce an ingredient, don't eat it.
Weigh yourself no more than once a week, and expect it to take at least two months to lose 15 pounds. One to two pounds per week is a healthy rate of weight loss. To keep yourself encouraged, track your progress in inches as well as pounds -- you might not see any movement on the scale one week, but you might have lost circumference.
Focus on your goal. If you want to lose weight before an event, post images that remind you of the event around your house. Have a buddy remind you and encourage you. Break your goal into smaller pieces and reward yourself -- with something other than food -- when you achieve them.