How many grams typically are removed going from a 40h bra size to DD?

Thank you for the question.
There is no direct correlation between the amount of tissue removed and the ultimate cup size that a patient will wear after breast reduction surgery.  There is simply too much variability among bra cup manufactures to make it a useful metric when it comes to preoperative communication and/or post operative predictions.
 In my practice, I would ask that you be as close as possible to your long-term stable weight prior to proceeding with elective breast surgery. Achieving this way will improve safety of the operation and decrease chances that additional surgery will be necessary down the line.
Before undergoing the breast reduction procedure it will be very important to communicate your size goals with your surgeon (who you should choose very carefully). Most patients wish to achieve enough of a reduction to help with their symptoms while remaining proportionate with the remainder of their torso. 
With the goal of improving communication with my patients I find the use of photographs of “goal” pictures (and breasts that are too big or too small) very helpful. For example, I have found that the use of words such as  "proportionate” or "DD cup” means different things to different people and therefore prove unhelpful. Also, as you know, cup size varies depending on who makes the bra; therefore, discussing desired cup size may also be inaccurate. 
Once you have communicated your goals carefully, your plastic surgeon will be able to provide you with an estimation of how much tissue will need to be removed, in order to achieve your desired outcome.
Best wishes with your breast reduction procedure; hopefully you will be very pleased with the outcome of the procedure performed.

Hello and thank you for your excellent question. Unfortunately, dealing with insurance companies is often a challenging task. Your best option to see if your procedure is covered, is to contact your insurer to get details about coverage and requirements before approval for surgery (as you are doing). Given the difficulties of dealing with insurance, you can consider paying out of pocket for the surgery. For our patients, the out-of-pocket expenses for an insurance plan often approximate (or even exceed) the cost for the procedure. You can then obtain documentation from your surgeon to attempt to get reimbursement from your insurer. Any treatment plan should be based on a detailed discussion with equal input from both you and your surgeon.   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.   Preoperative visualization and surgical simulation with the Crisalix system may help with your decision. The most important aspect is to find a surgeon you are comfortable with. I recommend that you seek consultation in person with a qualified board-certified plastic surgeon.  Good luck! 

Best,

Jon Ver Halen, MD FACS 

Harvard educated plastic surgeon