Does fat end up being absorbed if too much is transfered?

Thank you for your question. It all really depends on the patient. If there is not a good enough space for the fat to be transferred into, then it will not survive. Grafted fat has to survive off of surrounding tissue that is alive, so if a massive amount of fat is transferred and does not have living tissue to be surrounded by, then yes, it will not survive. There is a limit to what can be achieved and safety should be the number one priority. I hope for your sake that you had your procedure done by a plastic surgeon who is board certified by the American Board of Plastic Surgery. Hope this helps!Dallas R. Buchanan, MD, FACSOwner & Board-Certified Plastic SurgeonVIVIFY plastic surgery

The laxity of the skin and size of the buttocks affects how much fat can be injected and be absorbed. The results immediately following surgery will be the largest due to swelling and lack of fat resorption.  The buttocks will continue to decrease in size for the first few weeks.   I have observed that between 4 and 6 weeks the buttocks tend to stabilize in volume.  Usually by 3 months, the swelling is minimal and totally resolved by 6 months.  

Thanks for your question. With Brazilian butt lift, patients can look forward to a double benefit: reducing areas of unwanted fat while gaining a perkier, rounded posterior. Each procedure must be planned according to the individual needs of patients, harvesting fat from target areas of the torso, thighs or knees and transferring it to create smooth, attractive contours optimized for each person. We also put a little extra to account for loss of fat post operative, which is reabsorbed gradually by the body. Around 70% of fat that is grafted is typically expected to survive long term.

The controversy surrounding the "permanence" or "temporary" nature of the results buttock augmentation via autologous fat grafting speaks to the variable nature of fat grafting as a technique.
Technically speaking the results of fat grafting should be permanent in the sense that grafted fat which has becomevascularized should not disappear several months post op.
However, there is an initial period, immediately post op where some of the grafted fat is lost. It is during this period that some may sense that their aesthetic outcome is fleeting. Every patient reaches a point after which the grafted fat which has become vascularized is permanent and the fat graft which has not will have undergone resorption. This is typically reached by 3-4 months post op. 
For some patients, the graft take vs loss ratio will be favorable and for others less so. There is no question that there is both variability in techniques as well as outcome.
With regards to your specific question, once healed the results are permanent. Prior to that point there is some variability. Implants give a more consistent result. However, the less natural feel makes these options less desirable.
As always, you should seek a board certified plastic surgeon (ABPS) who is experience in both the science and art of autologous fat grafting to help you understand the procedure and provide a reasonable idea of what to expect both immediately post op and long term.

Hello dear!!
Thanks for the question and provided information as well.
After a BBL, only about 70% of the transferred fat cells will survive, so it is normal to see a minor reduction in your buttocks. If you have any concerns, I suggest you to follow up close with your plastic surgeon.
Good luck :)

There are three factors that lead to the result of a BBL: 1) how much fat the patient has to be removed an then transferred  2) The buttocks/hips - is the skin loose and able to accept large volume of fat   3) strict adherence to the post op recommendations. Sometimes, not often, there is not enough room to inject all the fat that was harvested. The patient has a small tight buttocks that won't expand to accept all the fat that was harvested. If you continue to inject the fat starts to come back out of the openings. Again, this is not common when 5L or less of lipoaspirate is removed in one setting because that is equivalent to ~500-900cc of solid fat. To use a high volume power injector, some fluid it left in the fat so these numbers look higher. If you go to a board certified PS that does a large number of this procedure, as much as safely possible will be injected. 

in order for a grafted fat to survive it has to have certain criteria. First the harvested fed needs to be healthy. If it's harvested at high vacuum or causing excess of mechanical trauma the tissues will be destroyed and will not be viable.  Each grafted particle of fat needs to be surrounded by live vascular tissue. The fat after being harvested has been stripped of its natural source of nutrients by having capillaries another blood vessels cut off. The harvested fat can only survive long term by having a new blood supply reestablished. This process is called neovascularization and happens between the second and the eighth day after the procedure. The ingrowth of blood vessels continue in size and strength over the next several weeks.  If a grafted particle of fat is surrounded by other particles of grafted fat rather than live vascular tissue it will not survive.  I referred to this as stacking fat and it is as your surgeon described self-defeating. Think of fat grafting as the chessboard with a black squares represent live vascular tissue as post tissue in the area being treated such as the buttocks. The white squares represent individual particles of harvested fat now devoid of blood vessels in the source of nutrients. For this process to work each white square needs to be surrounded by black squares. The black squares or live healthy tissue will sans the lack of oxygen through a variety of chemical signals like increased in acidity  which stimulates an increase in blood flow and blood vessel growth called angiogenesis. At this point the body has only a few days to reach each graph that a particle of fat with a new blood vessel before the fat dies.  During this early process the grafted fat stays alive only from the nutrients of the surrounding fluid. This process is called plasmatic imbibition. Eventually budding capillaries reach the grafted particles of fat and deliver actual red blood cells with oxygen. The tissues are extremely fragile to mechanical disruption at this point. This is why we asked patient to not sit or put pressure on the areas treated with fat transfer for the first several weeks. If a particle of fat that is just received its first in growth of capillaries gets physically distorted the capillary can break cutting off the new blood supply. Grafted tissue will only stay alive through plasmatic imbibition for a few days. When we as plastic surgeons graft  other tissues like skin grafts or bone grafts we typically immobilize areas by putting them in the splints in casts.  This immobilization allows and disrupted healing through the various stages of graft survival and healing. Over grafting leads to a higher percentage of graft failure. Successful fat transfer is always based on grafting small amounts of fat into many different planes in layers at different depths so that each grafted particle can be surrounded by live vascular tissue. Simply injecting large amounts of fat in a single space will inevitably lead to failure of the graft with fat necrosis and the fat liquefying into oil. This puts the patient at risk for complications and undesirable aesthetic outcomes  It is not uncommon to have more fat than is needed during a BBL procedure. There are two options at that point. One is to throw away the extra fat the other is to simply leave it fat by not completing the liposuction with the idea of having a second round of liposuction with the second round of fat transfer. For those patients who have excess amounts of fat and desire the most dramatic change having two or more sessions a fat transfer will always lead to a better outcome than overdrafting in a single session. Having several series of fat transfer is going to be more expensive and require several recoveries  It is therefore much less common.  The decision of how to approach each patient is very individual and will vary based on the surgeons experience, believes and training. The short answer to your question is yes. Generally the plastic surgeon and the patient have the same goal. This is generally to achieve the best aesthetic outcome with the least chance of complications or need for revisions. Have faith.  Best, Mats Hagstrom M.D.