The purpose of a breast lift is to correct sagging, drooping breasts (mammary ptosis). The surgery can be performed with or without an augmentation.
The breast lift surgically repositions the breast tissue to a higher level onto the anterior chest wall. In addition, the procedure re-drapes and removes the excess breast skin. There are many different techniques and surgical methods to correct mammary ptosis, mostly depending upon the degree of sagging.
Of all the cosmetic procedures performed, breast lift surgery is the hardest to master! Therefore, I would strongly recommend seeing a board certified, plastic surgeon who is very experienced with this procedure.
A change in your body weight may very well impact a change in your breast volume. Weight loss, depending on the amount, may cause the breasts to sag again. I would recommend that you are close to your desired weight before having breast lift surgery.
If you do experience a mild to moderate change in your weight that requires a breast lift revision, usually the surgery is minor without adding any additional incisions/scars. If major weight loss occurs, then the breast lift revision operation becomes more complex.
Thank you for your question, and I hope this helps.