More than 1 billion children, adolescents and adults live with obesity around the world, making it the most common form of malnutrition in many countries, according to an analysis published Thursday in the journal The Lancet.
This staggering statistic was reached earlier than anticipated, driven in large part by the rapid transition of malnutrition in the form of underweight to obesity in low-income and middle-income countries, Dr. Majid Ezzati, senior author of the analysis and professor at Imperial College London, said in a news conference Thursday.
Previous estimates by the World Obesity Federation suggested that there would be 1 billion people living with obesity by 2030, but that number was already surpassed in 2022, Ezzati said.
“We’ve really been taken aback by how fast things have happened,” he said.
The new global analysis, conducted by more than 1,500 researchers from the Non-Communicable Diseases Risk Factor Collaboration and the World Health Organization, analyzed the height and weight measurements of over 220 million people from more than 190 countries.
The analysis focused on rates of underweight and obesity, both forms of malnutrition that are detrimental to people’s health. Adults were classified as obese if their body mass index (BMI) was greater than or equal to 30 and classified as underweight if their BMI was below 18.5. Children and adolescents were defined as obese or underweight based on age and sex criteria by age, according to the study.
“Undernutrition and obesity are two faces of the same problem, which is the lack of access to a healthy diet,” Dr. Francesco Branca, director of the WHO Department of Nutrition and Food Safety, said in the news conference.
The analysis estimates that nearly 880 million adults and 159 million children lived with obesity in 2022. Obesity rates among children and adolescents worldwide increased fourfold from 1990 to 2022, while obesity rates among adults more than doubled.
“It is very concerning that the epidemic of obesity that was evident among adults in much of the world in 1990 is now mirrored in school-aged children and adolescents,” Ezzati said in a news release.
While obesity rates increased, the number of people affected by underweight fell in most countries. Obesity rates are now higher than rates of underweight in two-thirds of the world’s countries, according to the analysis.
This transition has been most evident in low-income and middle-income countries, particularly in Polynesia and Micronesia, the Caribbean, and the Middle East and North Africa. These countries now have higher obesity rates than those of many wealthy industrialized countries, according to the analysis.
The island nations of Tonga, American Samoa and Nauru had the highest prevalence of obesity in 2022, with more than 60% of the adult population living with the condition, according to the analysis.
“In the past, we’ve been thinking about obesity as a problem of the rich. Obesity is a problem of the world,” Branca said.
Ezzati said the researchers were surprised to find that none of the industrialized wealthy nations – except the United States – were at the top of the list for countries with the highest prevalence of obesity in 2022. He said that was a big change from 2017, when WHO last did a similar global obesity analysis, which found the US, Canada, Australia, New Zealand and the United Kingdom in the top category for prevalence of obesity.
“What this shows is that this transition is very rapid. We cannot wait to get rid of underweight to deal with obesity,” Ezzati said.
Branca said this obesity transition is the result of the rapid restructuring of food systems worldwide that has not been governed by public policy.
“The reason why the epidemic has progressed so quickly is because policy action has not been incisive enough,” he said. “There has been a reliance on behavior change, but [solutions] have not touched the structural element, which is the policies around food and environment.”
Obesity and underweight co-exist in many countries and must be dealt with in parallel, he said, through “double duty” policy interventions that address both forms of malnutrition.
Such policies include promotion and support of breastfeeding, taxation of sweetened beverages, regulation of food marketing that targets children and the provision of nutritious food in public institutions like schools, Branca said. He added that agricultural reform, urban design and primary health care investment can support those policies.
“Getting back on track to meet the global targets for curbing obesity will take the work of governments and communities, supported by evidence-based policies from WHO and national public health agencies,” Dr. Tedros Adhanom Ghebreyesus, the WHO director-general, said in a news release. “Importantly, it requires the cooperation of the private sector, which must be accountable for the health impacts of their products.”
Branca said public policy must aim to improve monitoring of food manufacturers and ensure equitable access to healthy, nutritious food for everyone. Over 3 billion people in the world still cannot afford a healthy diet, he said.
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“One of the roles of policy is to bring good health to people before they are wealthy,” Ezzati said.
To support these policies, WHO has partnered with other agencies like the United Nations International Children’s Emergency Fund to release frameworks such as the Global Action Plan on Child Wasting and the Acceleration Plan to Stop Obesity.
Experts also highlighted policy changes worldwide that have led to encouraging results. France, which saw a plateau in its obesity rates in the analysis, has implemented a national plan called Programme National Nutrition Santé that sets objectives for nutritional policy at the industry, consumer and research levels.
Countries in South America have begun implementing front-of-package nutritional labelling that includes clear warnings about fat, sugar and salt levels. Mexico led the way on taxation of sweetened beverages, and in Chile, processed foods cannot be marketed to children, Branca said.
“The community interventions which integrate promotion of healthy diet and physical activity have been particularly effective,” he said.