Open Letter to Insurance Companies, Regarding Mandatory Pre-bariatric Surgery Diet Regimens

To: Insurance Company, Medical Director
From: American Society for Metabolic and Bariatric Surgery (ASMBS)
Re: Mandatory Pre-bariatric Surgery Diet Regimens

It has become increasingly apparent that some bariatric surgery policies are mandating 6-12 month documented preoperative weight loss before approving bariatric surgery. This hurdle is unfortunate for several reasons. There are NO studies documenting the efficacy of this approach. There are several studies which show that a) there is no benefit in terms of long-term weight loss and compliance (1), b) it leads to patients dropping out of the bariatric approach (2), c) there is evidence that this leads to further aggravation of obesity co-morbidities when compared to patients who undergo bariatric surgery (3), and d), most disturbing of all, there is an increased mortality in patients who have been evaluated for bariatric surgery but do not undergo it for insurance denial or other reasons. (4-6) There are also five control, cohort studies which document a decreased mortality in patients who undergo bariatric surgery vs. those who do not. (7-11)

This issue should not be confused with data suggesting that weight loss immediately prior to bariatric surgery may be beneficial by decreasing the size of the liver, making the laparoscopic approach technically less difficult which could be associated with a decreased postoperative morbidity. Immediate preoperative weight loss may also be associated with a better long-term weight loss outcome. (12-15)

We believe that almost all of these patients have had numerous attempts at dietary weight loss, through multiple programs, over many years. 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 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.

We would like to take this opportunity to share with you our recent position statement (16) with literature review (attached) and hoping it can be used to update your bariatric surgery coverage policy references and requirements.


Robin Blackstone, MD, ASMBS President
Jaime Ponce, MD, ASMBS President-Elect, Insurance Committee Chair
John Morton, MD, ASMBS, Access Committee Chair


  1. Janz E, Larson CJ, Methiason MA, Kallies KJ, Kothari SN. Number of weight loss attempts and maximum weight loss before Roux-en-Y laparoscopic gastric bypass surgery are not predictive of postoperative weight loss. Surg Obes Relat Dis 2009;5:208-11.
  2. Jamal MK, DeMaria EJ, Johnson JM, et al. Insurance-mandated preoperative counseling does not improve outcome and increases dropout rate in patients considering gastric bypass for morbid obesity. Surg Obes Relat Dis 2006;2:122-7.
  3. Harakeh AB, Burkhamer KJ, Kallies KJ, Mathiason MA, Kothari SN. The natural history and metabolic consequences of morbid obesity for patients denied coverage for bariatric surgery. Surg Obes Relat Dis 2010 (in press).
  4. MacDonald KG, Jr., Long SD, Swanson MS, et al. The gastric bypass operation reduces the progression and mortality of non-insulin-dependent diabetes mellitus. J Gastrointest Surg 1997;1:213-20.
  5. Flum DR, Dellinger EP. Impact of gastric bypass operation on survival: A population-based analysis. J Am Coll Surg 2004;199:543-51.
  6. Sowenimo OA, Yood SM, Courtney J, et al. Natural history of morbid obesity without surgical intervention. Surg Obes Relat Dis 2007;3:73-7.
  7. Christou NV, Sampalis JS, Liberman M, et al. Surgery decreases long-term mortality, morbidity, and health care use in morbidly obese patients. Ann Surg 2004;240:416-23.
  8. Sjostrom L, Narbro k, Sjostrom CD, et al. Effects of bariatric surgery on mortality in Swedish Obese Subjects. N Eng J Med 2007;357:741-52.
  9. Adams T, Gress R, Smith S, et al. Long-term mortality after gastric bypass surgery. N Eng J Med 2007;357:753-61.
  10. Peeters A, O’Brien P, Laurie C, et al. Substantial intentional weight loss and mortality in severely obese. Ann Surg 2007; 246:1028-33.
  11. Busetto L, Mazza M, Miribelli D, et al. Comparative long-term after with laparoscopic adjustable gastric banding versus non-surgical controls. Surg Obes Relat Dis 2007;3:496-502.
  12. Riess KP, Kothari SN, Baker MT, Lambert PJ, Mathiason MA. The effect of preoperative weight loss on laparoscopic gastric bypass outcomes. Surg Obes Relat Dis 2008;4:704-8
  13. Still CD, Benotti P, Wood GC, et al. Outcomes of preoperative weight loss in high-risk patients undergoing gastric bypass surgery. Arch Surg 2007;142:994-8.
  14. Alami RS, Morton JM, Schuster R et al. Is there a benefit to preoperative weight loss in gastric bypass patients? A prospective randomized trial. Surg Obes Relat Dis 2007;3:141-5.
  15. Alger-Mayer S, Polimeni JM, Malone M. Preoperative weight loss as a predictor of long-term success following Roux-en-Y gastric bypass. Obes Surg 2008;18:772-5.
  16. ASMBS Position Statement on Preoperative Supervised Weight Loss Requirements. Sur Obes Relat Dis 2011;7:257–260.