Obesity: Blame Your Food Intake More Than Declining Activity

By Stacy M. Brown
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.

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.