An extensive study by Proceedings of the National Academy of Sciences (PNAS), spanning 34 populations worldwide, has found that increased calorie intake — not decreased energy expenditure — is the primary factor fueling rising obesity rates in economically developed societies.
Researchers analyzed data from 4,213 adults in communities ranging from hunter-gatherers and pastoralists, to industrialized nations. The study reported that while body mass, body fat percentage, and BMI were higher in more developed populations, total daily energy expenditures were also higher, reflecting larger body size.
Among African American adults, nearly 48% are clinically obese, including 37.1% of men and 56.6 % of women, according to the American Psychological Association. The association noted that disparities in stable housing, income, education, and access to healthy food and safe places for physical activity all contribute to these disproportionate rates of obesity and related health risks.
Recently, while speaking on CNN’s “News Night with Abby Phillip”, former New York Rep. Jamaal Bowman emphasized African Americans are disproportionately affected by issues such as obesity due to longtime discrimination.
“The reason why heart disease, and cancer, and obesity, and diabetes are bigger in the Black community,” Bowman said, “is because of the stress we carry from having to deal with being called the n-word, directly and indirectly every day.”
Obesity is a national and local epidemic. According to health officials in Washington, D.C., more than half of all adults are overweight or obese, with rates rising to over 72% in Wards 7 and 8.
District data show that less than one in every 10 White residents is obese, while one in every three African Americans in the District is obese. The Bureau of Cancer and Chronic Disease has stated that strategies to improve access to healthy foods and opportunities for physical activity are essential to prevention and management.
The 2019 Maryland Behavioral Risk Factor Surveillance System reported that only 52% of adults engage in the recommended 150 minutes of physical activity per week. Data from 2020 shows that 66.5% of Marylanders over age 18 are considered overweight or obese. Health officials have described obesity as a precursor to chronic diseases such as prediabetes, diabetes, cardiovascular disease, and some cancers.
In Virginia, nearly two-thirds of adults were overweight or obese in 2021, according to a report by the Joint Commission on Health Care. The report found that about 47% of Black individuals and 30% of Hispanic individuals were obese. It also noted that obesity diagnoses among Virginia Medicaid members rose 222% between 2014 and 2021, compared to a 4% increase in the general population.
“Obesity is a leading cause of global mortality and morbidity, accounting for more than 4 million deaths and 140 million disability-adjusted life years worldwide each year,” the authors wrote. “Fundamentally, weight gain results from consuming and absorbing more calories than are expended.”
The latest research, published in PNAS, measured total energy expenditure using the doubly labeled water method and examined the relationship between expenditure and measures of body composition.
After adjusting for body size, total and basal energy expenditures were approximately 6% to 11% lower in more developed economies; however, the differences were highly variable and did not consistently correspond with lifestyle.
“Comparisons of energy expenditure across populations strongly suggest that increased energy intake (i.e., caloric consumption and absorption) is the primary factor promoting overweight and obesity with economic development,” according to the report.
Among the 25 populations for which dietary data were available, the proportion of ultra-processed foods in the diet was positively associated with body fat percentage.
“We found some support for an obesogenic role of ultra-processed foods in the current dataset,” the study stated.
Researchers at PNAS reported that the estimated effect of decreased energy expenditure accounted for only about one-tenth of the increase in BMI and body fat percentage associated with economic development.
“Increased energy intake has been roughly 10 times more important than declining total energy expenditure in driving the modern obesity crisis,” the authors concluded.
The study also noted that while diet plays a central role, physical activity should not be overlooked.
“Daily physical activity has a broad range of well-documented health benefits, from reducing all-cause and cardiovascular mortality to improving mental health, and is an essential component of a healthy lifestyle,” the paper noted.
The study emphasizes that managing food is key to health.
“Regulating food environments to maximize the benefits of increased calorie availability without promoting a nutrient-poor, obesogenic diet remains a crucial challenge in public health that will only become more acute as economic development continues globally,” PNAS researchers wrote.