Bariatric surgery for severe obesity: the role of patient behavior.

In the United States, 34% of adults were obese (BMI > 30 kg/m2) in 2005-2006.1 Of particular concern is the rapid increase within the most extreme weight categories, resulting in the heaviest individuals becoming heavier.1,2 The prevalence of severe obesity, defined as BMI > 40 or approximately > 100 lbs. overweight, increased by 50% from 2000 to 2005, with 1 in 20 Americans now severely obese.2 Severely obese individuals, compared to those who are less overweight, have higher rates of obesity-related comorbidities and higher health care expenditures, compared to those who are less overweight.