Unfortunately, there is no way to achieve fat loss in a targeted area of the body without paying attention to the entire body. If you want skinnier knees, you must reduce your overall body fat while strengthening the muscles around the knees with exercise.
Stimulate total body-fat loss with proper nutrition. Boost your metabolism and energy levels by getting adequate protein, which will also ensure that your weight loss comes from losing fat, rather than muscle. Choose protein sources such as lean meats, eggs and lean dairy products. Allowing some fat in the diet will help you maintain energy as you reduce your caloric intake, and will help keep you full between meals.
Develop a cardiovascular training program that you can perform several times a week. Ideally, you should get 30 to 45 minutes of aerobic exercise, five times a week. However, any amount of cardiovascular exercise will help boost your metabolic rate, burning more calories and thus more fat. Choose exercises that target your leg muscles. Running, or using an elliptical machine or a stair machine will tone your legs for the appearance of slimmer knees.
Perform strength-building exercises. Building muscle in your legs will increase your metabolism, so you will burn calories even when you are not exercising. The look of your knees will improve when you tone your quadriceps, or thigh muscles. Effective exercises include lunges, squats, and leg extensions. Do three sets of 15 to 30 repetitions for each exercise, at least once a week.