In the United States, approximately 70% of adults and 33% of children and adolescents are overweight or obese.1,2 Although it is widely accepted that there are a variety of genetic, behavioral, and environmental determinants, the strength of the associations of individual risk factors with obesity is only small to moderate. Other than bariatric surgery, no pharmacologic or behavioral weight loss treatments have been found to consistently result in large sustained weight losses. One reason for the lack of stronger associations with risk factors or more consistently successful treatment is that all types of overweight and obesity are often grouped together. This approach potentially obscures strong associations between risk factors and specific subtypes of obesity.