Research findings by the Imperial College London School of Public Health and World Obesity reveal the drivers behind the rising number of people around the globe living with obesity, prompting calls for an ever-more urgent and holistic response.
One in eight people worldwide is now living with obesity, a global analysis by Imperial’s School of Public Health.
The researchers estimated that 159 million children and adolescents and 879 million adults were living with obesity in 2022. Highlighting changes to global trends in malnutrition over more than 30 years, the analysis published in The Lancet finds that the total number of children, adolescents and adults worldwide living with obesity has now surpassed one billion.
Study results from 2022 figures indicate the obesity rate was four times higher in 2022 than in 1990, more than doubling in women, rising from 8.8% to 18.5%, and almost tripling in men, from 4.8% to 14.0%. In the large-scale study, researchers analysed weight and height measurements from over 220 million people aged five years or older, representing more than 190 countries. A total of 63 million people aged five to 19 and 158 million aged 20 years or older participated in the research study.
The congruence of the growing prevalence of obesity with the decreasing number of underweight people worldwide since 1990 means obesity is the most common form of malnutrition in most countries.
“Researchers set out to analyse trends in obesity and underweight, both forms of malnutrition which are detrimental to health in many ways,”
Ryan O’Hare, Media Manager of Medicine at Imperial College London, told IFIS Publishing. The work follows previous estimates of the global burden of obesity and underweight, carried out by the same group in 2017.
Insight into worldwide obesity rates and changes
To examine worldwide trends in underweight and obesity from 1990 to 2022, researchers pooled the analysis of 3663 population-representative studies with 222 million children, adolescents, and adults.
“According to the researchers, the latest findings highlight an urgent need for comprehensive policies to tackle the burden of malnutrition, including improving the accessibility and affordability of nutritious food, as well as prevention and management strategies for obesity and underweight,” O’Hare details.
Imperial’s School of Public Health shows that in 2022, an estimated total of almost 880 million adults lived with obesity. This figure, four and a half times the 195 million recorded in 1990, indicates how obesity rates have considerably increased over the past 30 years.
In the latest results, combining the number of adults with the 159 million children living with obesity globally, over one billion people were personally impacted by obesity in 2022. While the double burden of malnutrition remains, with considerable numbers of people living with obesity and being underweight, figures for underweight people worldwide were 93 million fewer than those recorded in 1990.
A shift has subsequently occurred, where, in most countries, a larger number of people are affected by obesity than being underweight. In 2022, obesity rates were higher than rates of underweight for girls and boys in around two-thirds of the world’s countries.
Measuring height and weight in representative samples of the general population, the researchers used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults 20 years and older and school-aged children and adolescents aged between five and 19 years, from 1990 to 2022.
For adults, the researchers report the individual and combined prevalence of obesity, measured by taking the Body Mass Index (BMI) of 30 kg/m2 or more. To report obesity in school-aged children and adolescents, the researchers report a BMI of more than two standard deviations (SD) above the median of the WHO growth reference.
The NCD Risk Factor Collaboration (NCD-RisC) conducted the study in collaboration with the World Health Organization (WHO). The UK Medical Research Council, UK Research and Innovation (Research England), UK Research and Innovation (Innovate UK), and the European Union funded the study.
A preventable cause of other health conditions
The World Obesity Federation, creators of World Obesity Day, which aims to drive global efforts to reduce, prevent, and treat obesity, also released data gleaning further insights into the drivers behind obesity levels. The Federation’s understanding of obesity drivers is illustrated in the ‘ROOTs of obesity’ analogy, which highlights the many drivers of obesity, from genetic risk to unhealthy diets, physical inactivity, and healthcare access.
“This year’s World Obesity Atlas focuses on obesity as a preventable cause of other non-communicable diseases,” Magdalena Wetzel, Head of Policy and Advocacy at World Obesity, told IFIS Publishing. Specifically, World Obesity looks at the proportions of these diseases attributable to overweight and obesity in adults and children.
This year’s Atlas, in line with the theme of “Obesity and…”, highlights how obesity impacts other non-communicable diseases. For adults, the Federation presents the proportion of death and disease from diabetes, stroke, coronary heart disease, and cancer that is attributable to overweight and obesity. For children, it provides estimates of the numbers of children with early signs of NCDs, such as hyperglycaemia, high blood pressure, and low HDL cholesterol, and the proportion of these attributable to overweight and obesity.
“While acknowledgement of this relationship is not new, this is the first time the extent of the relationship has been presented in this way,” Jaynaide Powis, Head of Data and Evidence at World Obesity, told IFIS Publishing.
The Atlas found that the percentage of adult deaths attributable to overweight and obesity ranged from 5% of cancer deaths to 42% of type 2 diabetes deaths. At the same time, World Obesity estimated that in 2020, 41 million cases of low high-density lipoprotein (HDL) cholesterol in young people were attributable to excess body weight, 34 million high blood pressure and 15 million hyperglycaemia.
Previous Atlases have explored other themes, including the economic impact of obesity and the rise in childhood obesity. On World Obesity’s Global Obesity Observatory, users can explore data on some specific drivers by country, such as breastfeeding levels and the consumption of certain foods.
Growing obesity rates in children and adolescents
Obesity rates in children and adolescents prompt elevated concerns for public health.
“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,” Professor Majid Ezzati of Imperial’s School of Public Health and senior author of the study, said.
In 2022, nearly 160 million children and adolescents were affected by obesity, amounting to 65 million girls and 94 million boys, compared to 31 million in 1990. Global obesity rates more than quadrupled in girls, from 1.7% to 6.9%, and boys, from 2.1% to 9.3%, with increases seen in almost all countries.
“This new study highlights the importance of preventing and managing obesity from early life to adulthood, through diet, physical activity, and adequate care, as needed,” Dr Tedros Adhanom Ghebreyesus, WHO Director-General, said.
Making nutritious food available and accessible
“To successfully tackle both forms of malnutrition, it is vital we significantly improve the availability and affordability of healthy, nutritious foods,” Professor Majid Ezzati stated following the research.
Findings indicate that more than one billion people worldwide are living with obesity, which is more than the industry thought. “This is greater than what was estimated by World Obesity Atlases in previous years, which means not only that policy inertia is still an issue, but the counter-forces of the unhealthy food and beverage industry that drive the obesity epidemic, particularly in low-and-middle-income countries (LMICs), have redoubled their efforts,” Wetzel explains.
Contrary to public perception, the Atlas also shows that lower-income countries are increasingly leading the way in terms of disability and early death due to obesity and the diseases it is driving.
“The rapid rise of obesity and it becoming the biggest health issue in some parts of the world, like the Pacific Islands, as both the Atlas and Lancet illustrate, informs the urgency with which action needs to be taken and in increasingly lower-income communities, contrary to the biased view that obesity is a high-income country problem,” Powis emphasises.
“If countries react to the urgency of addressing the obesity crisis in a meaningful and impactful way, food manufacturing sectors will see a surge of regulations to curve demand for healthier food products,” Wetzel says.
The Lancet study's researchers corroborate the importance of proactive efforts to improve nutrition for all.
“A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesity.”
Action from leaders
The research will likely lead many to ask whether the data and its findings will now inform regulations, policies and campaigns.
“To create a healthier world, we need comprehensive policies to address these challenges,” Dr Guha Pradeepa, study co-author from the Madras Diabetes Research Foundation, said.
Research into industry interference in policy processes is essential for governments to guarantee a right to health in all policies.
“Further research on the relationships between diseases will strengthen our ability to care for individuals but should also provide impetus to policymakers to adequately address the drivers,” says Wetzel.
More research on monitoring and surveillance is also needed to understand the scale and distribution of obesity within populations. World Obesity also calls for investment cases so countries can direct resources to the most appropriate and cost-effective actions.
“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. Importantly, it requires the cooperation of the private sector, which must be accountable for the health impacts of their products,” Ghebreyesus added.
Editorial notes
Source:
Interview with Jaynaide Powis, Head of Data and Evidence at World Obesity
Interview with Magdalena Wetzel, Head of Policy and Advocacy at World Obesity
Interview with Ryan O’Hare, Media Manager (Medicine) at Imperial College London
