You don't have to lose 10% - the CA DMHC has ruled that this requirement is unnecessary, and if you ask them to waive the requirement, they generally will do so. See this document, which you can point out to Kaiser and tell them that their requirement is inappropriate:
http://www.dmhc.ca.gov/aboutTheDMHC/org/boards/cap/BariatricREV.pdf
Page 2:
http://www.dmhc.ca.gov/aboutTheDMHC/org/boards/cap/BariatricREV.pdf
Page 2:
Mandated weight loss prior to indicated bariatric surgery is without evidence-based support. Mandated weight loss prior to indicated bariatric surgery leaves the patient at increased risk from the patient’s comorbidities. Mandated weight loss prior to indicated bariatric surgery is not medically necessary. Mandated weight loss prior to indicated bariatric surgery would be deviant from the standard of care practiced in the United States and other published countries. The risks of delaying bariatric surgery, while not entirely known in the short-term, are real and can be measured. Any potential value of losing weight prior to bariatric surgery is theoretical and not supported by any data. An experimental study including fully informed consent to determine if there were a reduction in risks or other benefit from mandated weight loss prior to bariatric surgery is indicated.