Is it okay to loose 15-20 pounds after a BBL? I'm currently 170 pounds and 5"6.

Thank you for your question. I think it is important to be an ideal weight before elective surgery as you do not want fluctuations in your body to affect your surgical outcomes. You can certainly lose weight (that is up to you) and being healthier should always be a goal. However, you should be aware that if you lose weight, you may lose weight in areas sensitive to weight loss. Good luck! 
Best wishes, 
Dr. Suzette Miranda 

Dear dwinie,loss of weight after a BBL will have a negative impact on your results. You can expect some loss of your transferred fat. This is one of the main reasons why it is the best to reach goal body weight before the surgery.  Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery 
Member, Am. Society of Plastic Surgery