Obesity rate's climb may have stopped in 'promising' sign

The nation’s obesity rate may be falling after decades of increases, a newly released federal study finds, and experts say weight-loss drugs could be a key reason.

The rate of Americans 20 and older who have obesity fell from 41.9% in the 2017-20 survey period to 40.3% in the August 2021-August 2023 period, according to the National Center for Health Statistics report, which was released early Tuesday.

The nation’s obesity prevalence had been steadily increasing since the National Health and Nutrition Examination Survey began measuring it in 1960, when 13.4% of those 20 to 74 had obesity. Current data includes those older than 74.

The drop of 1.6 percentage points, the largest of only three declines since 1960, is within the 1.9-point margin of error, cautioned the lead author of the report, Samuel D. Emmerich, an epidemic intelligence service officer with the statistics center, in an interview.

But Dr. Fatima Cody Stanford, an associate professor of medicine and pediatrics at Harvard Medical School and an obesity medicine physician at Massachusetts General Hospital in Boston, said the data is "promising."

"We need to see continued trends in the overall population to get out our confetti and wave our flag and say that we're getting success," she said.

Dr. Christine Ren-Fielding, chief of bariatric surgery for NYU Langone Health, said she was not expecting the apparent decline because "nothing has really changed in our society in terms of food quality and food production and this need to have more," especially of processed foods that are high in sugar, salt and fat.

"You would think that the only thing that really changed is the introduction of" drugs, such as Ozempic, Wegovy, Mounjaro and Zepbound, she said. "So you have to, by deduction, say that it was a significant factor contributing to the decrease in the obesity rate."

Dr. Eileen Barr, an obesity physician in East Setauket, said the new drugs are being released at a time when more primary care physicians "are becoming more conscious that obesity is a disease ... and they see the impact of obesity on hypertension and diabetes and cancer, so they realize how important this preventative medicine is."

Insurance companies often won't cover weight-loss medications — although they do when used for diabetes — despite the medical benefits, she said. The drugs usually cost more than $1,100 a month, she said. People desperate for cheaper versions sometimes resort to buying them online from disreputable companies, she said.

The drop in obesity rates eventually could lead to decreases in rates of heart disease, diabetes, stroke and other conditions, said Dr. Sotiria Everett, a clinical assistant professor in the Renaissance School of Medicine at Stony Brook University and a registered dietitian. It will be years before the answer is clear, she said.

The survey did not break down data locally. A separate survey, the federal Behavioral Risk Factor Surveillance System, found that New York had one of the lowest obesity rates in the country, 28%, in 2023. The 2021 survey found that Nassau County had a lower rate than the state has a whole — 24.9%, compared with 29.1% for the state that year — while Suffolk’s rate was slightly higher than the state’s, at 29.4%.

That survey is of self-reported weight and height, the combination of which is used to calculate body mass indexes. BMIs of 30 or higher indicate obesity. BMIs of 40 or higher mean severe obesity.

The National Health and Nutrition Examination Survey includes weighing and measuring people in person, which is more accurate, Emmerich said.

"When it's based on self-reporting, that leads to an underestimate of obesity prevalence, because people tend to overestimate their height and underestimate their weight," he said.

Nearly 6,000 people were in the newest survey. The study found that women were more likely to have obesity than men, and people without college degrees were more likely to have obesity than college graduates.

Despite the decline in obesity rates, the rate of severe obesity rose, from 9.2% in 2017-20 to 9.7% in 2021-23, the study found. That, too, is within the margin of error, of 0.7%.

"With severe obesity, there are certain socioeconomic groups who may have less access to these healthier food choices, they may not have safe places to exercise, and they may not be able to engage in health care services," Stanford said.

In addition, she said, stress and mental health conditions such as depression and anxiety have increased since the COVID-19 pandemic began and are linked to severe obesity. Some people are more genetically predisposed to severe obesity, she added.

Dr. Dominick Gadaleta, vice chair of surgery at North Shore University Hospital in Manhasset and a bariatric surgeon, said U.S. attitudes toward food play a major part in obesity rates. Immigrants have lower obesity rates than their U.S.-born children, he noted.

There are some positive trends, such as healthier options in some restaurants and calorie counts on menus, Gadaleta said. But for many people, especially in low-income areas, ultraprocessed, unhealthy foods are still more easily accessible than fresh, healthy foods, and they’re often cheaper, he said.

Major challenges remain in weaning Americans off unhealthy diets and reducing the obesity rate long-term, Ren-Fielding said. Processed foods have advantages that fresh fruits and vegetables don’t, she said.

"Processed foods physiologically provide people more satiety [sense of fullness] than non-processed foods," she said. "And it's not just satiety, but the combination of sugar, salt and fat — particularly the sugar and salt components — in these processed foods that is somehow driving the urge to crave these foods. It's something that wholesome foods do not provide."

Check back for updates on this developing story.

By David Olson

david.olson@newsday.com@DavidOlson11

David Olson covers health care. He has worked at Newsday since 2015 and previously covered immigration, multicultural issues and religion at The Press-Enterprise in Southern California.