Wasn't Sheldon writing about water fasting? Remember that Water Fasting slows down the metabolic rate much more than the Master Cleanse. Also, it is a much more intensive cleanse. As was previously posted, the transition period for Master-Cleanse is usually about 1/2 the time of the fast, although this is not explicitly explained in the book. To avoid weight gain it is vital to allow the metabolism to get back to pre-fast levels before returning to previous eating patterns (most of us should never return to those patterns). After getting the digestive system back on track, stick to a low calorie nutrient dense diet. The "Eat To Live" plan outlined by Joel Fuhrman in his book of that title is ideal for post fast eating.