My wife was two years after the baby up to a 14 from a 4 and after months on medifast went down to a 3 as did her sister and aunt also do well.
I'm up some and I am going to try eating between a 4-6 hour window and fasting the rest of the time (drinking water or maybe eating a 20 calorie salad).
I have a friend who is doing the fasting 2 days a week and says it works for him.
The other extreme is the water only diet for several days until the body goes into the state where it is consuming body fat.