Some people can lose a lot on the MC, but others lose very little. If you are 70 pounds overweight (honestly overweight and not aspiring to look like a super model), then you may need to look into possible hypothyroid problems that can contribute to a slow metabolism. If this is a problem with you, then fasting is probably the worst thing you can do to lose weight. Fasting, even a mild fast like The Master Cleanse can further slow down the metabolic rate because the body senses it is not getting food and goes into a starvation mode, it slows down to conserve its reserves. You will be much better off doing The Master Cleanse with a goal of cleansing the body, especially the digestive system so it will be able to absorb nutrients better. As the Master-Cleanse cuts through layers of accumulated gunk lining the gut, the essential nutrients of foods will be absorbed and the waste will pass through faster. Then continue with a nutrient dense low calorie diet like the "Eat For Life" diet by Dr. Joel Fuhrman that will help you lose weight quickly and safely, and be able to keep it off. The Master Cleanse may help a few people lose excess weight rapidly, but, without a total change of lifestyle and eating habits, then the weight will quickly come back. If the metabolism has slowed down significantly, then even more weight will be added and will be much more difficult to lose. Fasting is the worst method for permanent weight loss. You may find it is a blessing that you have lost relatively little weight because now you can reap the benefits of a good cleanse and know you must learn to change your eating habits for the better.
Im wish I could give you more encouraging news. I realize the press has given the Master-Cleanse a lot of hype as a quick weight loss diet. However, they fail to mention the weight loss is only temporary if a proper diet is not kept in place for life.