Based on various research studies, here is how much weight loss you can expect from a given level of exercise:
Walking - 1 hour, 3 times per week (or a half-hour per day): roughly 1/4 pound per week
Walking - 1 hour per day, 7 days a week: roughly 1 pound per week
Walking - 1 hour, 3 times a week, plus Weightlifting, 1 hour, 3 times a week: roughly 1.2 pounds per week
Running, 3 times per week for 30 minutes: roughly 1/2 pound per week
Weightlifting, 3 times per week for 30 minutes: roughly 1/5 pound per week
I could post many other figures, but you get the idea. Keep in mind that these numbers are averages, and that everyone responds differently. Also, if a person chooses to do aerobic exercise only, they are in danger of losing some muscle mass as well as fat. A small bit of weightlifting can counteract this trend.
Overall, these numbers show what is needed to lose weight in a safe and healthy manner. In comparison to diets, where one loses the weight and it eventually comes back, with exercise there is no rebound effect. Exercise volume can be reduced back to a maintenance level (walking a half-hour a day) after the goal weight has been achieved.
