Global burden of adult overweight and obesity

Overweight and obesity in adults have become defining features of global health in the 21st century. According to the World Health Organization, in 2022 about 2.5 billion adults aged 18 years and older were overweight, and within that group roughly 890 million were living with obesity. This corresponds to 43 percent of adults being overweight and 16 percent living with obesity, meaning that close to two in three adults remain within a weight range that is either above or well above what is considered metabolically healthy.

These figures are not static outliers. Worldwide adult obesity has more than doubled since 1990, and the share of adults who are overweight has risen from about 25 percent in 1990 to 43 percent in 2022. This shift has taken place within a single generation, which underlines that the human genome has not changed on this timescale. What has changed very rapidly is the environment in which people live, eat, move and work.

The distribution of excess weight is also uneven across regions. WHO data show that in 2022 the prevalence of adult overweight ranged from about 31 percent in the African Region and the South East Asia Region to about 67 percent in the Region of the Americas. These regional contrasts reflect differences in income, food systems, urban design, social inequalities and cultural patterns, yet in every region the direction of change over recent decades has been upwards.

At the same time, many low and middle income countries now experience a double burden of malnutrition. WHO reports that undernutrition and obesity often coexist in the same country, the same community and even the same household. (World Health Organization) It is therefore no longer meaningful to think of underweight as a problem of poorer countries and obesity as a problem of richer ones. Rather, the global food and activity environment increasingly produces both forms of malnutrition side by side.

From a health perspective, excess adiposity is not simply a cosmetic concern. Overweight and obesity are closely linked to a higher risk of noncommunicable diseases such as type 2 diabetes, cardiovascular diseases and several cancers. (World Health Organization) WHO also describes unhealthy diet and lack of physical activity as leading global risks to health, because they contribute not only to obesity but also to metabolic disturbances such as hypertension and dyslipidaemia, which in turn drive heart disease and stroke.

The scale of the problem, combined with its health consequences, has prompted growing attention from researchers and policy makers. A recent analysis within the Global Burden of Disease program, published in The Lancet and widely reported, projects that if current trends continue, around 60 percent of adults worldwide could be overweight or obese by 2050. The projection itself is not a certainty about the future, yet it is a statistically grounded warning that current trajectories are incompatible with long term metabolic health.

Modern lifestyles, metabolic health and the need for integrated strategies

The rapid rise in adult overweight and obesity illustrates a widening mismatch between human biology and modern environments. WHO and other international bodies describe how changes in dietary and physical activity patterns are often the result of broad environmental and societal changes. These include development patterns that encourage car based transport, sedentary work, urbanization without adequate green or active spaces, and a food system that makes energy dense, nutrient poor products cheap and ubiquitous.

In many cities, daily life is structured around sitting. Long hours of screen based work, entertainment delivered through digital platforms and transport that replaces walking and cycling all reduce routine energy expenditure. WHO has previously noted that physical inactivity is among the top ten risk factors contributing to death globally, and that regular physical activity helps prevent overweight and obesity while also improving cardiovascular and metabolic health. (World Heart Federation) When this pervasive inactivity is combined with abundant access to ultra processed foods high in added sugars, fats and salt, weight gain becomes a highly predictable population outcome.

Dietary shifts have been equally important. OECD and WHO analyses highlight that over recent decades diets in many countries have moved towards higher consumption of processed and ultra processed foods, sugar sweetened beverages and fast food, often at the expense of minimally processed plant based foods. These products are heavily marketed, convenient and engineered to be highly palatable, which reinforces frequent consumption. For individuals, making healthier choices in such an environment requires constant effort and often higher financial cost, especially where fresh, nutrient dense foods are less accessible or more expensive.

Because the drivers of obesity operate at many levels, isolated interventions are rarely sufficient. Both WHO and the OECD emphasize that effective responses combine individual level support with structural changes in the wider environment. On the nutrition side, this can include fiscal policies, food labelling and marketing restrictions. WHO has described taxes and subsidies that influence food and beverage prices as part of a broader package of regulatory policies that can improve the food environment. Evidence reviewed by WHO and UNICEF shows that taxes on sugar sweetened beverages reduce purchases of these drinks and encourage reformulation, which is associated with lower sugar intake and potential reductions in weight gain over time. Complementary strategies such as mandatory front of pack nutrition labelling can help consumers identify healthier options more easily and can push industry towards healthier product profiles.

On the physical activity side, urban planning and transport policy shape everyday movement. WHO’s work on urban health highlights how lack of safe walking and cycling infrastructure and limited access to green spaces contribute to physical inactivity and obesity in cities. Measures that make active transport safe and convenient, integrate physical education and activity into schools and create public spaces that invite movement can shift population level activity patterns without relying solely on individual motivation.

Health systems themselves also have a role. Obesity is often underdiagnosed and undertreated in primary care, even though it is a major risk factor for noncommunicable diseases. Integrating structured nutrition counselling, physical activity prescription and, when appropriate, pharmacological or surgical treatment into routine care can help people who are already living with excess weight reduce their health risks. WHO’s recognition of obesity as a chronic disease that requires long term management is part of this shift in perspective.

The economic argument for integrated strategies is increasingly clear. OECD analysis finds that every dollar invested in preventing obesity can generate economic gains up to six times that amount, through reduced health care costs and improved productivity. This means that aligning food systems, urban design, transport, education and health policy with metabolic health is not only a public health priority but also a rational economic choice.

Taken together, the statistics on adult overweight and obesity describe a world in which the average environment pushes body weight upward, even among people who are trying to live healthily. The fact that over 43 percent of adults are overweight and 16 percent live with obesity is therefore not simply a story about individual choices. It reflects the cumulative effect of decades of policy, commercial incentives and urban development that have unintentionally normalized energy dense diets and sedentary living.

Rising obesity rates make this mismatch between modern lifestyles and metabolic health impossible to ignore. Reversing current trends will require integrated strategies that act on nutrition and physical activity together, and that operate at the level of systems rather than solely at the level of willpower. The data are clear that the burden is already high and still growing. They are equally clear that reshaping environments to support healthier diets and more active lives can yield large health and economic dividends, and can begin to realign human biology with the world in which people now live.