Will losing 30 pounds after BA affect results?

Good question, and one it seems like you may already know the answer to! If your history of weight gain or loss hasn’t had much impact on your breast size, you probably don’t have much to worry about if you lose the weight you want to. However, it’s better in general if you try your best to maintain a stable, healthy weight. Again, everyone’s body is affected differently by weight loss and gain, so as long as you are satisfied with the results, you should be just fine.

The breast is composed of glandular breast tissue and fat.  At age 18 it is very likely that most of your breast volume is glandular.  If this is the case it is unlikely that losing weight will make a big change in your breasts.  The fact that it loss in the past did not seem to affect her breasts is a further encouraging factor.

The short answer is, yes, if you lose weight, your breast will get slightly smaller, but so will all other areas of your body so your body proportions will stay the same.  There are some slight variations in this, such as women who have nearly all glandular tissue for breast tissue as opposed to mostly fatty tissue for breast tissue.  The ones with glandular tissue would not decrease as much, while people with fatty tissue would see a more of a decrease.  Best wishes.