Would 250ccs of fat enough to increase an empty 36B breasts size by 1 cup size? If not, how much at least would I need? (Photo)

At size 36 B, each 200 cc of fat corresponds to 1 cup size change. Unfortunately, not all the fat transferred survives. If you want to achieve 200 cc volume of fat, you would need to transfer approximately 300 cc of fat, which would corresponds to 1 cup size change. However, from your photograph, your breasts are low on the chest wall and widely separated. More important than fat transfer would be a breast lift. The technique I recommend is The Bellesoma Method. This will reshape your breast tissue creating upper pole fullness without implants, elevate them higher on the chest wall and more medial to increase your cleavage. Vertical scars are avoided, nipple sensation (in 95%) and the ability to breast feed are maintained.

Best Wishes,

Gary Horndeski, M.D.

I appreciate your concerns, however you do have options, both with pros and cons.
Implants have a solid and reliable history with very high patient satisfaction rates but they must be replaced every 12-15 years. Fat grafting has the advantage of using your own body's material to increase breast size, but only small augmentation is possible. The 250 mL recommendation revolves around research which demonstrates that fat transfer to the breast in greater amounts usually does not take or takes sporadically. There is always uncertainty about how much fat will "take", increasing the possibility of asymmetry and need for revision. Be sure to consult with a board certified plastic surgeon to help you navigate this decision. Good luck!