What is a healthy amount of time to lose 20 pounds?

Typically 2 pounds per week is healthy so 10 weeks to loose 20 pounds. Every person is different. If you are starting off at a heavier weight 40 pounds overweight you will/can healthy loose more weight per week (approx 3-5 pounds per week) so 4-7 weeks . I would recommend starting off with 2 or 3 pounds off per week make it your goal. Wait at least 2 weeks before weighing yourself once you start your diet/exercise routine. Daily or weekly weight-ins will most likely cause you to give up. GOODLUCK!