Half of US adults will be obese by 2030 with a quarter projected to have severe obesity: Study

Researchers also found that the prevalence of obesity will approach 60% in some states and no state will have an obesity prevalence of less than 35%


                            Half of US adults will be obese by 2030 with a quarter projected to have severe obesity: Study
About half of the adult US population will have obesity and about a quarter will have severe obesity by 2030. (Harvard T.H. Chan School of Public Health)

Obesity is going to get worse in the US: 1 in 2 American adults nationwide will have obesity by 2030, and the prevalence will be higher than 50% in 29 states.

This shows that about half of the adult US population will have obesity, according to a new study led by Harvard T.H. Chan School of Public Health.

The researchers also found that the prevalence of obesity will approach 60% in some states and no state will have an obesity prevalence of less than 35%. According to lead author Zachary Ward, programmer/analyst at Harvard Chan School's Center for Health Decision Science, 35% is considered to be a high level for the past few years. Accordingly, the team projects that what will be the best states with the lowest obesity prevalence are going to be at the same level as some of the worst states.

What is even more concerning, says Ward, is the rise in severe obesity. According to the analysis, nearly 1 in 4 adults are projected to have severe obesity by 2030 -- which is over a 100 pounds usually of excess weight -- and the prevalence will be higher than 25% in 25 states. The researchers say this has been a surprising finding as severe obesity has typically been a rare condition, but they found that it is growing rapidly in a lot of states.

Obesity is defined as a body mass index (BMI) of 30 or higher, and severe obesity is a BMI of 35 or higher.

The projections, says the team, are troubling because the health and economic effects of obesity and severe obesity take a toll on several aspects of society.

“Obesity, and especially severe obesity, is associated with higher risks of diseases such as diabetes, heart disease, and cancer, as well as increased risks of death. The growing obesity epidemic in the US, therefore, has large public health implications and negative consequences for life expectancy. The high projected prevalence of severe obesity among low-income adults and the high associated medical costs also have substantial implications for future health care costs in the US, especially for Medicaid,” Ward told MEA WorldWide (MEAWW).

Obesity is defined as a body mass index (BMI) of 30 or higher, and severe obesity is a BMI of 35 or higher. (Getty Images)

The analysis shows that some areas of the country are at a higher risk for severe obesity and some demographic groups are also at a much higher risk for severe obesity.

The researchers project that nationally severe obesity will become the most common BMI category for women, non-Hispanic Black adults and for low-income adults, who make less than $50,000 annually (that is, the annual household income). They also found that for very low-income adults -- whose annual household income is less than $20,000 -- severe obesity will be the most common BMI category in 44 states.

“Although severe obesity was once a rare condition, our findings suggest that it will soon be the most common BMI category in the patient populations of many health care providers. Given that health professionals are often poorly prepared to treat obesity, this impending burden of severe obesity and associated medical complications has implications for medical practice and education,” says the team in their findings.

For the study, the researchers used self-reported BMI data from more than 6.2 million adults who participated in the Behavioral Risk Factor Surveillance System Survey (BRFSS) between 1993 and 2016. Body mass index is calculated by dividing a person's weight in kilograms by the square of their height in meters. Since self-reported BMIs are frequently biased, the team used statistical methods to correct for this bias.

The results show that by 2030, several states will have obesity prevalence close to 60%, while the lowest states will be approaching 40%. 

About half of the adult US population will have obesity and about a quarter will have severe obesity by 2030. (Harvard T.H. Chan School of Public Health)

“Our projections show that the national prevalence of adult obesity and severe obesity will rise to 48.9% and 24.2%, respectively, by 2030, with large variation across states. Based on current trends, our projections show that the prevalence of overall obesity (BMI, ≥30) will rise above 50% in 29 states by 2030. We also project that the prevalence of severe obesity (BMI, ≥35) will rise above 25% in 25 states,” says the study published in the New England Journal of Medicine.

The prevalence of overall obesity ranges from 41.5% in California and 42.8% in New York to 58.2% in Mississippi and 58.4% in Oklahoma.

The projected state-specific prevalence of adult obesity and severe obesity for some of the states in 2030. (New England Journal of Medicine/Harvard T.H. Chan School of Public Health)

The researchers estimate that currently, 40% of American adults have obesity and 18% have severe obesity.

“We were not able to explore possible causes of the obesity epidemic in this paper, but our findings of large disparities in obesity prevalence by sex, race/ethnicity, and income suggest that there are likely many reasons for this growing epidemic. As a result, it seems unlikely that any one strategy will be able to solve this problem,” Ward told MEAWW.

The findings, says the team, will help policymakers as it gives them a better sense of where things are headed, and which groups are more at risk. For example, previous research suggests that sugar-sweetened beverage taxes have been a cost-effective intervention for curtailing the rise in obesity rates.

The researchers say since it is difficult to lose weight and it is very hard to treat obesity, prevention will be key to combat and better manage this growing epidemic. “Given the difficulty in achieving and maintaining meaningful weight loss, our findings highlight the importance of prevention efforts – it seems clear that we will not be able to treat our way out of this epidemic. In other work, we have identified some cost-effective policy and environmental prevention interventions, such as a sugar-sweetened beverage excise tax. More research is needed to identify cost-effective interventions with a large population reach, and how efforts to maintain a healthy weight can be successfully sustained from childhood across the entire life course,” Ward told MEAWW.

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