I do not know why you would not be approved for a tummy tuck based on the information you provided.
I can tell you that you should get as close to your goal weight as possible prior to surgery to improve not only your cosmetic result but to lower the incidence of wound healing issues.
Speak to a plastic surgeon to formulate a plan for you. (Mark Deutsch, MD, Atlanta Plastic Surgeon)
If you ready your goal weight of 160lbs, you would be a good candidate for tummy tuck. In tummy tuck, excess lower abdominal skin/fat is removed and muscle is plicated to tighten the abdomen.
Right now, you have some excess intra-abdominal fat that would make your tummy tuck result not optimal.
However, with your weight loss, you can have a great result. Please reach your stable goal weight and consult a board-certified plastic surgeon. (Sugene Kim, MD, FACS, Houston Plastic Surgeon)
You will probably have to ask more questions from your PCP as to why he is not supportive of you having a tummy tuck.
He may just want you to get to your goal weight before considering. Every surgery can have a complication no matter how small and having a tummy tuck is considered major surgery.
Being at a lower weight for your height will not only enhance your results but make it safer for you. (Anh Lee, MD, El Paso Plastic Surgeon)
PCP says NO to having tummy tuck
It is possible that you have a lot of visceral fat that cannot be improved with a TT. Only an in office exam can determine this.
Back pain and sciatica do not typically improve with a TT, but can de worsened during recovery.
It is best to get this corrected first. All the best. (Paul S. Gill, MD, Houston Plastic Surgeon)