by Julie Fidler, Natural Sociey:
One of the largest surveys of health in the United States reveals some sobering, though not entirely unexpected news: Americans are fatter than ever. Ouch.
The CDC has been asking Americans 18 and older about their health and their family members’ health every year since 1957. The National Health Interview Survey, which contains data from 2015 on more than 100,000 people, shows that more Americans had health insurance and smoked fewer cigarettes in 2015 than in previous years, but obesity and diabetes rates are still climbing.
In 2015, 30.4% of Americans age 20 and older said they were obese, up from 29.9% in 2014. It’s not a huge increase, but it represents a continuation of a trend that has been going on since at least 1997, when researchers began using the current survey format. At that time, the obesity rate was only 19.4%. 
Brian Ward, health statistician at CDC’s National Center for Health Statistics and one of the authors of the report, told CNN:
“That is not a good trend there. But it is not necessarily anything unexpected.”
However, according to other surveys, the obesity problem is far worse than the CDC’s suggests. In 2012, the National Health and Nutrition Survey found that 34.9% of adults age 20 and over were obese. To reach their conclusions, the researchers behind that survey measured the height and weight of more than 9,000 Americans to calculate their body mass index (BMI). The current survey relied on respondents self-reporting their body size.
Michael W. Long, assistant professor at the Milken Institute School of Public Health at George Washington University, said the National Health and Nutrition Survey is probably more accurate, because people tend to exaggerate their height and downplay their weight.
That’s a discouraging thought. The CDC’s findings show that more than 97 million U.S. adults are grossly overweight, but that number might actually be much higher.
Other findings from the CDC survey included: