Over the past 20 years, the prevalence of overweight and obesity has increased in the US, the researchers state.
The authors of the research letter, published in JAMA Internal Medicine, are Dr. Graham A. Colditz and Lin Yang of the Washington University School of Medicine, St. Louis, MO.
Their paper describes an analysis of the most recent data taken from the National Health and Nutrition Examination Survey (NHANES, 2007-12) to calculate the prevalence of overweight and obesity.
Researchers had conducted a similar study around 20 years ago, analyzing data taken from 1988-1994 to work out the chronic disease burden associated with body mass index (BMI). The findings of that study were used to inform clinical practice and prevention strategies.
"Compared with 1988-1994, the distribution of the population's weight status has increased in the past 20 years," write the authors of the new research letter. "The rising trends in overweight and obesity warrant timely attention from health policy and health care system decision makers."
In the new analysis, overweight was defined as a BMI between 25.0 and 29.9. Obesity was defined as a BMI of 30.0 and above and was divided into three different classes. BMIs of 30.0-34.9 were defined as class 1, BMIs of 35.0-39.9 were class 2 and BMIs of 40 and above were class 3.
Data were obtained for 15,208 men and women aged 25 and above in a sample representative of over 188 million adults. The researchers estimated that around 36.3 million men (39.96%) and 28.9 million women (29.74%) were overweight, with around 31.8 million men (35.04%) and 35.9 million women (36.84%) obese.
These findings make alarming reading when considering that overweight and obesity are associated with numerous chronic health conditions, including type 2 diabetes, heart disease and stroke. There is also a financial cost to the problem; the American Heart Association (AHA) estimates that obesity costs $190 billion each year in weight-related medical bills.
Strategies to reduce modifiable risk factors are recommended
Such is the scale of the problem that a Gallup Poll conducted in November 2013 found that obesity was considered to be the third most urgent health problem facing the US, behind cost and access but ahead of cancer and heart diseases, the two leading causes of death in the country.
Dr. Donna H. Ryan - professor and associate executive director for clinical research at the Pennington Biomedical Research Center at Louisiana State University in Baton Rouge - suggests a number of possible triggers for the obesity epidemic.
These suggestions include changes to sleep patterns, increased availability of food and more sedentary lifestyles fueled by the decreased physical demands of many jobs and increased "screen time" with the use of televisions, computers and smartphones.
"Population-based strategies helping to reduce modifiable risk factors such as physical environment interventions, enhancing primary care efforts to prevent and treat obesity, and altering societal norms of behavior are required," state the authors.
Dr. Ryan believes that society must learn to treat obesity as a disease rather than a consequence of a lack of willpower, becoming more accepting of people with the condition:
"If you have not had a friend, family member or colleague who has struggled with their weight and particularly if you haven't tried to lose weight yourself, then it's easy for you to ascribe negative stereotypical traits to overweight and obese people. It's a lot like alcohol and drug addiction. Our society is more accepting of these conditions as a disease and less so for obesity."
Previously, Medical News Today reported on a study finding that stepping on the scales daily and tracking the results on a chart is an effective way of losing weight and keeping it off.