Even small changes in your weight can make a difference. If you shed just 1 pound, you'll take 4 pounds of pressure off of your knees. Drop 10 pounds and you'll take 40 pounds of pressure off.
The more pounds you lose, the better. If you're overweight, experts suggest you aim for 10% of how much you weigh now. For instance, if you weigh 200 pounds now, try to lose 20 pounds. Aim for a loss of 1-2 pounds a week.