40 pounds away from goal weight - Will my breasts sag again if I lose weight after I get a breast reduction and lift?

As you mentioned it is best for you to reach your goal weight and maintain it before having surgery. For some women when they lose weight they notice a significant change to their breasts, while others don't. A 40 pound weight loss is pretty significant and would likey result in some impact on your results.

I counsel my patients they will have the best results if they can be as close as possible to their ideal weight prior to surgery. Weight gain or loss will change results.

Hello,
And thank you for the question.
I always encourage my patients to be at their optimal weight prior to surgery, but sometimes, if they hit a plateau, especially if heavy breasts/pain interfere with exercising, we still proceed with surgery understanding that the risk of complications is higher with higher BMI.
If you were to lose 30-40 lbs after the surgery, it may change the breast shape.
I suggest that you seek an in person consultation with a Board-Certified Plastic Surgeon specializing in Breast Reduction surgeries to further discuss your options, specific techniques, concerns and expectations. Make sure you specifically look at before and after pictures of real patients who have had this surgery performed by your surgeon and evaluate their results.
I hope this helps.Best regards, Dr. Karanetz
Dr. Irena KaranetzBreast Fellowship-TrainedBoard Certified Plastic Surgeon