By Stacy M. Brown
NNPA Senior National
Correspondent
An extensive study 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 percent are clinically obese, including 37.1 percent of men and 56.6 percent of women, according to the American Psychological Association.
The association has 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. “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 paper stated.
The research, published in the Proceedings of the National Academy of Sciences, 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,” the authors wrote. 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 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 emphasized 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 authors observed that rising economic development has introduced widespread access to ultra-processed foods, which may disrupt satiety signals and encourage higher calorie absorption.
“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,” the researchers wrote.
