Rising obesity rates worldwide may be contributing to the climate crisis, researchers report.
"Our analysis suggests that, in addition to beneficial effects on morbidity, mortality and health care costs, managing obesity can favorably affect the environment as well," said study corresponding author Faidon Magkos, from the department of nutrition, exercise and sports at the University of Copenhagen, in Denmark.
Like other oxygen-dependent creatures, humans emit carbon dioxide that's produced by metabolic processes necessary to live, the scientists explained.
The amount of carbon dioxide -- a greenhouse gas -- produced by a species is determined by its average metabolic rate, average body size and the total number of individuals of the species.
Obese people produce more carbon dioxide than those of normal weight, the researchers said.
Also, obese people consume greater quantities of food and beverages that need to be produced and transported to them, and transportation of obese people requires more consumption of fossil fuels. This means higher carbon dioxide emissions related to food production and transportation for obese people, the study authors explained.
The researchers estimated that obesity contributes to an extra 700 megatons of carbon dioxide emissions per year worldwide, or about 1.6% of all human-caused emissions.
Overall, being obese is associated with about 20% more greenhouse gas emissions (carbon dioxide, methane and nitrous oxide) than being a normal weight, according to the study published online Dec. 20 in the journal Obesity.
"This has important implications for all those involved in the management of obesity," Magkos added in a journal news release.
The researchers stressed that these findings should not lead to more stigmatization for obese people, who already face negative attitudes and discrimination.
Ted Kyle is founder of ConscienHealth, an organization that works to find sound approaches to health and obesity. "This study makes it clear that we pay a steep price for making it difficult to access care for obesity. Not only does obesity affect the health of the individuals who have it, untreated obesity might also contribute to environmental issues," said Kyle.