Increase Breast Cup Size from Gaining Weight After Fat Transfer?

Dear Self Concerned Patient,
Micro Fat Grafting for Breast Augmentation in general will results in enlargement of 1 cup size. This is not true for all cases and depends a lot on how much fat there is for 'harvesting' and injection into the breasts. It can require more than one procedure and has associated risks which may increase the need to screening procedures for cancer.
It is a good procedure - and the results can be signifcantly improved with the 'BRAVA' bra.
The fat will increase with weight gain and decrease with weight loss.
With Warm Regards,
Trevor M Born MD

Fat transfer to the breast for breast augmentation is a procedure that only recently has become reliable. There are many questions to be answered about optimizing yield, but as far as the risk of cancer or cancer detection, those fears appear to be unfounded.
The risk of complications such as fluid collections, infections, or fat necrosis can be eliminated by using the correct methods of harvesting, processing, and injecting fat.
As to how much augmentation can be gained, it is reasonable to expect a 1 cup gain, but as surgeons become more experienced and develop new approaches, I expect the volume gains will improve.
I myself have obtained gains of more than a cup, although I tell my patients to expect 1 cup gain.
Breast size can increase after fat transfer if you gain weight. Those fat cells act as normal weight cells, and they will increase in volume as you gain weight. This is what I call the "fourth dimension" of body contouring. By taking fat from the areas you hate gaining weight and putting them where you want to increase volume, you get permanent alterations to your figure so weight gains may in fact ENHANCE your figure.

What you are describing is true -- if you gain weight, the transferred fat will behave like the fat from the area it came, and the fat can take up additional volume. An increase in 1 cup is proabably all you can expect.
However, fat transfer is not a widely accepted technique for breast augmentation for a variety of reasons from cosmetic and safety standpoints. Importantly, the cells can calcify, making interpretation of mammograms difficult. I would strongly encourage you to not undergo such a procedure and instead consider implants which produce safe and reproducable results.
Be sure you consult a board certified plastic surgeon about breast augmentation.
Good Luck!