Exercising with a sprained ankle requires that you adjust your workouts so you don't put excess weight on your injured ankle. Trying to lose weight while recovering from a sprained ankle is going to be challenging. A healthy weight loss of one pound a week might still be possible if you create a calorie deficit. Talk to your doctor before performing any exercise while recovering from an ankle sprain.
Eat healthful foods. Avoid snacking on processed foods while you are injured. Choose fresh fruits and vegetables, and foods that are low in fat and calories to help your body continue to lose weight even while you can't work out because of your sprained ankle. Just because you're not exercising at full capacity doesn't mean you should cut down on the amount of water you drink. Hydration and a quality night's sleep have as much to do with losing weight as diet and exercise.
Perform ankle stretches to restore flexibility and assist healing. Rotate your injured ankle in circles and point and flex your foot to bring mobility back to your ankle, if doing so does not cause pain at least three times a day. Do calf raises to improve your ankle flexion while keeping your ankles stable. Perform windshield wiper exercises for your sprained ankle. Sit in a chair and swish your affected ankle outward and touch the inside edge of your foot to the floor. Pivot the foot inward and touch the outside of your foot to the floor. Do two sets of up to 15 reps twice a day.
Exercise the rest of your body. Even if you can't stand or move your ankle, work out your upper body by performing presses, rows and situps. Burn calories through cardiovascular exercises that don't hurt your ankle. Swim, do aqua jogging with a flotation belt or use a rowing machine to keep weight off while your ankle heals without furthering your injury.
Walk with crutches to keep weight off your injured ankle, if your doctor has cleared you to do so, keep your body moving so you can burn fat. Avoid inactivity.