1) You can start the 6 mo diet, and challenge it at the same time:
http://asmbs.org/wp/uploads/2011/03/PreopWtLossRequirements-May2011.pdf
ASMBS Position Statement on Preoperative Supervised Weight Loss Requirements
Summary and recommendations
First, no class I studies or evidence-based reports has documented the benefits of, or the need for, a 6 –12- month preoperative dietary weight loss program before bariatric surgery. The current evidence supporting preoperative weight loss involves physician-mandated weight loss to improve surgical risk or to evaluate patient adherence. Although many believe benefits could result from acute preoperative weight loss in the weeks before bariatric surgery, the available class II–IV data regarding acute weight loss before bariatric surgery are indeterminate and provide conflicting results, leading to no clear consensus at this time. The preoperative weight loss recommended by the surgeon and/or the multidisciplinary bariatric treatment team because of an individual patient’s needs might have value for the purposes of improving surgical risk or evaluating patient adherence. However, it is supported only by low-level evidence in the published data at present.
One effect of mandated preoperative weight management before bariatric surgery is the attrition of patients from bariatric surgery programs. This barrier to care is likely related to patient inconvenience, frustration, healthcare costs, and the lost income resulting from the requirement for repeated physician visits not covered by health insurance.
It is the position of the American Society for Metabolic and Bariatric Surgery that the requirement for documentation of prolonged preoperative diet efforts before health insurance carrier approval of bariatric surgery services is inappropriate, capricious, and counterproductive, given the complete absence of a reasonable level of medical evidence to support this practice. Policies such as these that delay, impede, or otherwise interfere with life-saving and cost-effective treatment, which has been proved to be true for bariatric surgery to treat morbid obesity, are unacceptable without supporting evidence. Individual surgeons and programs should be free to recommend preoperative weight loss according to the specific needs and circumstances of the patient.
2) Are you seriously ill from your morbid obesity? Diabetic? High blood pressure? Can you assert that the longer it takes to get your morbid obesity under control, the higher your risk of death or disability from this unnecessary diet?
3) Can you assert that you have dieted numerous times in the past with the same, predictable results, which was temporary lost, followed by regain?
4) Do the diet, and try to get it waived at the same time.