Hi and thanks for your question. It’s always difficult to correlate the number of grams removed to a change in cup size. This is because different women’s breasts have different densities, so 100 grams in one woman may occupy a different volume than 100 grams in another woman. Furthermore, cup sizes are not standardized, so it can be difficult to judge the difference between any two cup sizes without actually trying a bra on, something that can’t be done during surgery when the patient is asleep. It’s easier to think about a reduction in terms of percent, for example, to reduce the breast size by about 40-50%. That being said, 100 grams of tissue is a small amount in general, and would be correlated more with just a breast lift, rather a noticeable reduction, especially for a patient who is larger then a B cup breast. A visit to a plastic surgeon's office will help you to understand if you're a candidate for the procedure, and what aesthetic outcomes are realistic in your particular case. In order to get a qualified, ethical, and expert opinion on your surgical options and expectations, always schedule an in-person office consultation with a plastic surgeon certified by the American Board of Plastic Surgery. Best of luck, Keith M. Blechman, MD New York, NY