In the United States, 27.1% of adults were obese in 2013, the highest rate measured since Gallup and Healthways began tracking in 2008. The obesity rate increased by nearly a full percentage point over the average rate of 26.2% found in 2012. As more Americans moved into the obese category in 2013, slightly fewer Americans were classified as overweight or as normal weight.
The Gallup-Healthways Well-Being Index, which uses respondents’ self-reports of their height and weight to calculate body mass index (BMI) scores, differs slightly from government reports of obesity, which are based on actual heights and weights found in clinical measurements. A recent government report based on the National Health and Nutrition Examination Survey found that 34.9% of adults ages 20+ in the study were obese. This rate had not significantly changed between 2003 and 2012.
Gallup and Healthways began tracking U.S. adults’ weight daily in 2008. Individual BMI values of 30 or above are classified as “obese,” 25–29.9 are “overweight,” 18.5–24.9 are “normal weight,” and 18.4 or less are “underweight.” For the past six years, nearly two-thirds of Americans have had BMIs higher than is recommended, while roughly 35% of Americans have been in the “normal weight” category.
The World Health Organization further classifies BMIs of 30.00 or higher into one of three classes of obesity:
- Obese class I = 30–34.99
- Obese class II = 35–39.99
- Obese class III = 40+
Those with BMIs of 40+ are often considered “morbidly obese.” According to Americans’ self-reports of height and weight, the percentage of morbidly obese has been slowly rising since 2011, and is now the highest Gallup has recorded, at 3.8%.
The percentage of Americans in obese class II has also been on the rise, reaching a record high of 6.3% in 2013. The percentage in obese class I has varied, but the 17.1% who fall into this group matches the highest rate recorded since tracking began. Thus, the overall increase in obesity in 2013 reflects an upward shift among all three obesity groups.
The majority of Americans who are obese fall into obese class I, which means they have less weight to lose to move into the overweight or, ideally, the normal weight category. But the increase in the percentage in the U.S. who fall into obesity classes II and III is troubling, given the fiscal and physical costs of obesity.
The obesity rates across all major demographic and socioeconomic groups in the U.S. increased at least marginally in 2013 compared with 2012, with the exception of those ages 18–29, which showed no movement.
Some of the groups with the highest obesity rates saw the largest increases from 2012 to 2013. The obesity rate increased by more than one point among Americans who make less than $36,000 a year, those ages 45–64, and those living in the South. The obesity rate among African Americans, already the highest rate recorded among major demographic groups, rose 0.9 points to 35.8% in 2013.