What are the long-term effects of this BBL procedure? Does the fat go away after many years?

Once the fat revascularizes, the fat should be permanent.  The fat cells may shrink and grow with weight loss and gain.

Thank you for your question. With Brazilian butt lift we transfer fat from one area of the body to the other.  These fat cells are transferred in microinjections throughout multiple planes in the buttock tissue so that they can gain new blood supply and live in their new home, providing increased volume and shape to the buttocks.  The fat that survives is there permanently. Around 70% of fat that is grafted is typically expected to survive long term. We also put a little extra to account for loss of fat post operative, which is reabsorbed gradually by the body. That said, you definitely have to choose your surgeon correctly and make sure that he/she has the training and experience to meet your goals with absolute safety.  Best is a Board Certified Plastic Surgeon with specialized expertise in this procedure.

BBL works via fat transfer. The fat that survives the process of grafting becomes a natural part of you behaving as it would if it had never be harvested. Thus it is susceptible to weight gain and loss as is all the fat in your body.There is no solid data for predicting the behavior of a particular population of fat cells. Patients will often lament that weight loss often precipitates changes in areas they had not anticipated or hoped for, i.e. "my breasts shrink and my tummy remains the same!"When an individual gains or loses weight, the fat cells swell or shrink. Thus after BBL, the donor sites will have a smaller population of cells which can swell or shrink. This does not mean you cannot gain weight in these ares, however, the logical conclusion is that weight gain is less likely. The same logic applies for grafted areas (buttock) which now have a larger population of fat cells (assuming graft take/vaibility). Some believe that the grafted fat cells will behave exactly as they did before (if you always gained weight in your abdomen and never lost then it would stand to reason that those fat cells from the abdomen would behave similarly in the buttock). Anecdotally, I have seen fluctuations of both types in patients. This is difficult to predict with any degree of certainty. As always, discuss your concerns with your board certified plastic surgeon.