Obesity and Weight Management

The growing prevalence of obesity is a global health concern. In 2009 to 2010, more than one-third of adults and 17 % of youth in the US were obese, as defined by body mass index (BMI). Obesity is associated with numerous health risks such as hypertension, cardiovascular disease (CVD), diabetes, stroke, and various cancers. Obesity also has a considerable impact on health-related quality of life (QoL). Of greatest concern is the early onset of obesity compared with previous generations. This has led to a predicted growth in the proportion of the population living with obesity-related diseases and chronic disabilities, which may reverse the trend toward increased life expectancy achieved during the past century. The economic costs of these obese populations living with chronic diseases will be dramatically higher than the normal-weight population. Clinical evidence suggests that weight reduction can improve outcomes in obese patients. Modest weight loss (2.6–4.9 kg) is associated with improvements in weightrelated comorbidities. Higher levels of weight loss have been associated with greater benefits. While any intervention to combat obesity should focus on lifestyle interventions, in particular increasing physical activity, health care systems could achieve substantial cost savings through supplementing such interventions with anti-obesity medications that promote weight loss. A growing consensus agrees that the main factors underlying the obesity epidemic are a rise in urbanization and globalization, which have led to substantial changes in the number and types of food-related cues, food availability and portion sizes, the availability of food at all hours of the day, and sophisticated marketing techniques. In the past it was believed that obesity prevention and treatment was a matter of self-control. This would imply that society has collectively lost its self-control in the last 30 years, in parallel with the rise in obesity, and that North Americans, in whom obesity levels are highest, have reduced self-control. However, this seems an unlikely explanation. The increase in obesity is seen across all socioeconomic groups, including those with high levels of education enabling the ability to make informed choices. The neurophysiologic mechanisms influencing food intake may therefore be operating below the level of individual awareness.