Is it okay to loose 15-20 pounds after a BBL? I'm currently 170 pounds and 5"6.

It's okay to lose weight after a BBL. Keep in mind that after a Brazilian butt lift your new shape is locked in. With weight loss your buttock is likely to get smaller but would maintain the same curves. #StayBeautiful @RealDrWorldWide

Ideal candidates are at a stable weight,  in good health , and have excess fat in some parts of the body and too little in other regions.  Gaining weight before the procedure is to no advantage and when you lose weight again the fat cells will shrink just like the donor site fat cells.  Typically, the transferred fat results in a significant increase in volume of the body site being treated.

General rule of thumb is to be within 10 pounds of your weight goal and maintain a stable weight prior to surgery.  I transfer as much fat as possible for each and every patient, so that the result is impressive even with small fluctuations in weight.
In most cases of weight loss, the buttocks and other areas with stored fat will become smaller.  About 50% of the fat that is transferred lives and becomes a part of you.  This will hold stable as long as there is no weight fluctuation.  The fat will not move, but losses in weight will distribute differently. The fat that lives in the buttocks from the procedure will get larger with weight gain and smaller with weight loss.
Kenneth Hughes, MD, Board Certified Plastic Surgeon
Los Angeles, CA