I would like to lose 20 pounds of fat while retaining my muscle. What is a realistic timeline? I am not in a super hurry, but, would like to lose it as quickly and efficiently as possible. A bit of background, I was 350 pounds at age 39, dropped down to 180 in about 16 months, was skinny fat as I did too much cardio and to little lifting, and for the last 3-4 years I have tried to add back muscle while staying as lean as possible, so a lot of back in forth between 190 lbs to 220lbs. I took the last year off of dieting to hold 220 in hopes of improving my metabolism and holding onto the muscle I have gained. I am currently 48 years old and would like to drop from 220 to 195 to 200 and stay there for the foreseeable future.