Breast fat transfer - does the fat stay?

Not all fat transferred survives and only 60% of the fat survives. The fat that does survives can be adversely effected by weight changes. If you lose weight then the fat can be decreased.

Gary Horndeski, M.D.

Thank you for posting your question here.
Fat grafting to the breast has been gaining traction recently since it uses your own tissue and there has been a trend of people preferring the use of natural materials over synthetic ones. It grows with you as you gain weight and it decreases as you lose weight so it keeps up with your general proportions.
Usually around roughly around 50-80% of fat transferred survives , this is dependent on multiple factors and for the most part is a little unpredictable , so some patients might need multiple sessions to achieve their desired outcome.
There is also a limit to how much fat can be transferred without compromising the transferred fat ( if you put too much , the fat you transfer will be far from the new blood supply so it won't survive.
The fat that doesn't survive for the most part is re-absorbed but in some individuals can form cysts or granulomas.
For someone who wants to change the size of their breast dramatically (a couple of cup sizes etc) I would recommend going for an implant. Fat grafting can be coupled with it if desired to improve contours etc but usually won't offer you as big of a change as what an implant would.
I hope this helps , good Luck!