Everyday health.com offers this tip for losing 20 pounds:

Physical activity helps counting calories. Being physically active burns calories while it improves your overall health. Aim for 30 minutes a day most days of the week. A brisk 30- to 45-minute walk burns 100 to 200 calories. If you can burn 200 calories through exercise, you only have to cut out 300 calories in food or drink to reach your daily calorie-cutting goal.