These results are based on more than 175,000 interviews conducted each year from 2013 to 2015 and more than 350,000 interviews conducted each year from 2008 to 2012 as part of the Gallup-Healthways Well-Being Index. Unlike some government estimates of obesity, the Well-Being Index uses respondents’ self-reported height and weight to calculate body mass index (BMI). It does not involve in-home clinical measurements that typically result in higher obesity estimates.

In addition to the 28.0% who are obese, another 35.6% of adults are classified as overweight, with 34.6% normal weight and 1.8% underweight, as reported in 2015.