I'd like to point out the reason why I, and others, stress that fasting (of any type) is a poor choice for those who's main priority is weight loss.
When a person fasts a lot of wonderful things happen. You take control (and responsibility) for the metabolic processes and natural cycles of your body that are normally on auto-pilot. Doing so enables us to focus the body's energies on particular organs or systems (in the case of juice fasting), or on the elimination of stored fat in an effort to release toxins (in the case of the MC). Weight loss is the key component of the Master Cleanse, it is the only way the MC can actually work. It is through the release of stored fat and shrinkage of our fat cells that a lifetime of stored toxins can be effectively flushed out of the system. (Otherwise the body simply just "can't reach them" so to speak).
MOST MC'ers are thrilled by the pounds of weight loss - but here is the catch. Biologically, the way our bodies are designed, as soon as you re-enter the world of eating (after ANY length of fast), your body is immediately lurched into rebuild mode. You've lost a LOT, and quickly, your body wants to quickly replenish what you've lost. Many people find increased hunger and cravings for fatty, sugary foods post-fast. Post-fast is more difficult for many than the actual fast!
This presents a very difficult challenge for those who wish to see their weight loss as permanent, and can lead to disappointment as the pounds return as quickly as they came off. This is why what you eat post-fast is so very important. Returning to pre-fast weight should be accomplished slowly, with only the healthiest of ingredients, fresh whole fruits and vegetables, whole grains, leafy greens. Many choose a predominantly raw and vegan diet for 1 - 2 months post-fast for this reason.
If you want the weight loss to be long term - do not think you can fast and then return to the ways that got you to your high weight. I only coach fasters listing weight loss as their main goal if they are truly ready to commit to a lifestyle change post-fast. This means totally revamping how, when, and what they eat. If you're not ready for a major overhaul post-fast then don't do it for weight loss. Your results will be short-lived. Long term weight loss is best obtained through good old diet an exercise, not fasting.
Raw vegans with limited gluten intake (eat very few grains) are the among only people who I ever see maintain most to all of fasting weight loss. For everyone else it is a big struggle, but can be accomplished through diligence, commitment, and very careful eating.
Hope this helps. It is truly not out of a 'holier than thou' attitude that people stress that fasting is not for those seeking a quick fix to weight loss...