Will my breasts sag after breast reduction?

Hello and thank you for your question.
It is best to be at your ideal/goal weight prior to having surgery. This will give you the best result. Consult with a board certified plastic surgeon to discuss your options. Best wishes!

As we age breasts change over time as well. After the surgery, your breasts will be smaller therefore they will sag far less than they would have before the operation. Unfortunately, age and effects of gravity will cause slight sagging even after your surgery.
If you are not at your target weight and would like to lose some weight, it's a good idea to do so before your operation. Losing a lot of weight after a breast reduction surgery could result in smaller breasts than you wanted as well as changes in skin and the overall shape of your breasts.
I suggest you achieve the desired weight and maintain it for a few months before booking your surgery. Best wishes.

Losing weight following your breast reduction may influence your results depending on the amount of weight lost and your unique physiology. It could contribute to sagging or a further decrease in breast size. On the other hand, it may not affect your results at all. It is difficult to say for sure although with the info you've provided, there is a good chance it would contribute to sagging.I usually recommend that my patients reach their stable and ideal weight before pursuing surgery. This improves surgical outcome and reduces the risks associated with surgery.