The extent of the problem of obesity.

The prevalence of obesity is increasing worldwide. In the United States, in 1999, 27% of adults had a body mass index >30 kg/m(2), almost double the prevalence of 20 years earlier. The estimated mortality from obesity-related diseases in the United States is approximately 300,000 annually and growing. In the future, mortality related to obesity is expected to exceed that of smoking. Numerous diseases are caused or made worse by obesity. These include type 2 diabetes; hypertension; dyslipidemia; ischemic heart disease; stroke; obstructive sleep apnea; asthma; nonalcoholic steatohepatitis; gastroesophageal reflux disease; degenerative joint disease of the back, hips, knees, and feet; infertility and polycystic ovary syndrome; various malignancies; and depression. Type 2 diabetes is perhaps the most visible obesity-related problem. Present in at least 14 million Americans, it leads to serious complications and premature death. It is largely caused by obesity, and is generally cured by weight loss. The quality of life of the obese is markedly reduced, and the costs to health care systems are great. Preventive programs have yet to affect the rising prevalence. An effective solution is needed.