Is the Master Cleanse Good to Lose 20 Lbs?

Hi i had a baby 7mo ago and i have not been able to lose weight. I only have a bowel movement once a week and wondered if i did the master cleanse would it help? I lost 20 lbs before when i was sick and was going to the bathroom everyday. I dont know if i have water weight or just backed up.i noticed my stomach is more saggy would a lipo help or tummy tuck? and what are alternatives that work for a saggy stomach