My breast size was 40DD. After I lost 30kg, it went down to 36C. Will my breast grow back if I gain 30kg? (Photo)

I expect that some of your breast volume will grow back. A full breast lift would be nice to tighten the skin back up. Best of luck on your pursuits 

The shore answer is yes.  Your breasts will gain the weight as well.  What I recommend is a breast lift without any implants and that will help shape and lift your breasts as well.  Good luckDr Vasisht

 Thank you for your question and photograph. It appears that you have lost a large volume of weight and therefore your breasts have shrunken as well. If you put weight back on, your breasts will likely get bigger as well. At this point, I think you would certainly benefit from a bilateral breast lift.  If you want your breasts to go back to the size that they were  without gaining weight, then you will certainly need breast implants to get the additional volume.  Unfortunately,  I don't think there is anyway to get back the breast volume that you desire without putting on additional weight 

Thank you for your question and photos. Likely, your breasts will increase in size if you gain weight. Other than weight gain, there is no natural or non-surgical way to effectively increase breast size. Based on your description of your breasts, it sounds as though you may be a good candidate for breast lift.If you are interested in a breast lift, I suggest that you consult with highly specialized plastic surgeons in your area to review your options. Best of luck, 

Because of the weight loss, your breast has lost volume and became more saggy.  If you gain the weight back, the breast may look what they were before the weight loss, but because of the large size, the your breast will be substantially saggier than now.  Without gaining weight, if you had breast lift, all the volume of the breast would be put together and lifted, and the breast would be higher and look larger.  I recommend that you consider breast lift.Good luck,Dr Alex Kim

Thank you for the question and picture. No, there is no "natural" way to increase your breast size without gaining weight.  Keep in mind, that if you were to gain weight, your breasts would remain in their current lower position ( you would likely end up with larger/low breasts, not necessarily the breasts you were used to prior to the weight loss). In other words, your breasts may have changed in position (with the weight loss), irreversibly.  Based on the photograph (assuming you have concerns about breast position), I think you are a good candidate for breast lifting;  in my practice, I would offer you a second stage breast augmentation procedure if you wish to increase breast size as well. I hope this, and the attached link, else. Best wishes.