At a weight loss rate of ½ -1 pound per week, it will likely take you at least 20 weeks to lose 20 pounds. Losing weight at this pace is safe and will help you keep the weight off long term. To accomplish a weight loss of ½ - 1
pound per week, try to burn an extra 250-500 calories per day by walking. If you find you're not burning this many calories by walking alone, simply reduce your calorie intake through diet in addition to walking.