Make sure you include the WW but also ask your surgeons office if they have any forms that could be sent to your pcp to fill out about each of your visits. This same thing happened to me. I feel the WW helped, I also wrote a personal letter and copied pictures from an overweight child to the present.
The form my surgeon sent to the PCP had the following:
Visit date
Month ___ of 6
Name
DOB
Weight
Height
BP, pulse, temp, glucose if diabetic
Weight loss meds tried in past
Weight loss meds not appropriate due to
Obesity related co-mobidities
Current medications
Diet education discussed
Exercise/activity discussed
Behavior modification goals set with patient
Return visit scheduled for
Signature , date
My PCP filled this out after my 6 months because the insurance company called my surgeon and said if they didn't get better PCP documentation they would deny it, took 24 hours to get this paper work back to them and 2 hours later I got my approval
Good Luck! It will happen!