to answer your question I went from a size 12 to a size 6 in 8 weeks. I fasted for 5 days to jump start it. After the fast I only ate 600 calories of all natural foods and exercized a great deal and I averaged about 5 lbs a week, loosing alittle over 40 lbs. So if I can do it eating, you can do it fasting! Good luck!