Trying to lean out after a BBL - will I lose my butt and hips?

Once the fat from a BBL is transferred and the appropriate blood supply is formed, that fat is there to stay.  It becomes a part of your body, like fat anywhere else, and the fat cells in that area will shrink and expand just like the fat everywhere else in your body.  When a patient loses weight, the fat cells in their butt could potentially shrink, but if that same patient puts a little weight back on, those cells should expand again, causing their bum to go back to the size they were post-BBL.  Some patients like to train their legs and glutes after a BBL to both lift and increase the size of the muscles in that area, providing an even more curvaceous appearance to their rear end.Best wishes!

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

Hello dear!!
Thanks for the question and provided information as well. 
After liposuction and BBL, you will lose weight in the same way as before. If you do lose weight, your BBL results could be affected.If you have any concerns, i suggest you to follow up close with your plastic surgeon.
Good luck :)