after getting denied the first time, I realized that most surgeons have a bunch of things that you need to get done before they send it to insurance. If you do your own legwork and get the specifics from your provider, you can dictate to your doctor what is and what is not necessary. Standard clearances are: cardiac (stress test), sleep apnea study, psychologist, nutritionist consult, blood work, gallbladder sonogram.....those you can't get around. Ideally, they want you to lose some weight before the surgery because it makes it easier for them to do the surgery. I only lost 4 pounds from my initial consult. Your insurance approval will be based on your starting weight, not how much you lose before surgery...trust me, the doc wants to collect his money, and won't sabotage your approval. They should have experts in his office to get it approved. I believe the 6 month thing is something they throw in there because some insurance companies require it. Mine, UHC, didn't. I sent them an email to request approval requirements, they replied with the answer, and I brought it in to the doctors office. My initial consultation was in May, I had my surgery August 16. They do want you to start a liquid diet 2-4 weeks prior to the surgery because this will be the diet you will be on for 4-6 weeks post-op. Mostly Protein shakes.
One other thing. I'm not sure if this helped, but I took photos of myself and also wrote a letter to the insurance company basically begging them to approve it. Hope this info helps.