Childhood Obesity Surpasses Underweight: A Growing Global Health Crisis
For the first time in history, global childhood obesity has surpassed underweight, affecting one in ten children and adolescents. Once a challenge confined to wealthy nations, obesity has now become a worldwide challenge. Childhood obesity is a complex, chronic condition that occurs when a child’s weight exceeds the 95th percentile for their age, height, and sex in children aged two years and older. Whilst the proportion of underweight children has decreased over the past few decades, obesity rates have risen at a significantly more rapid pace.
Historically, obesity was a concern limited to the Global North. However, recent data mark a turning point. The trend reflects a broader global shift in health patterns, as obesity—especially among children and adolescents—is just one of several non-communicable diseases that have increased dramatically in the 21st century. This rise stems from two interconnected factors. The first is environmental change, including rising air pollution, heat exposure, and decreasing water availability. The second is widespread behavioural change in food consumption, cultural practice, and lifestyle, which have contributed to the increasing rates of non-communicable diseases.
Today, obesity is no longer confined to high-income nations; it has become a truly global issue. According to UNICEF, “several Pacific Island countries have the highest prevalence of obesity globally, including 38 per cent of 5 to 19-year-olds in Niue, 37 per cent in the Cook Islands, and 33 per cent in Nauru.” These trends also persist in higher-income countries. However, Sub-Saharan Africa and South Asia remain exceptions to this trend.
The modern obesity epidemic began in the United States during the 1970s and 80s, before spreading across other Westernized, high-income nations. In the Global North, urbanization and industrialization reduced physical activity, as jobs shifted from physical to stationary labour. Advances in agricultural technologies enabled the mass production of high-yield crops, but also rendered most farm work obsolete. As workers left farms for offices, cars became more accessible and cities less walkable. People moved less during the day. At the same time, food became bigger, cheaper, and more abundant. People could afford to eat more, but the food they ate was often processed and low in nutritional value. To produce food on such a large scale, farmers relied on chemical fertilizers and over-farming, in turn depleting soil minerals and sacrificing nutritional value. As society moved less and ate more, obesity rates began to rise.
Until recently, obesity was a problem reserved for wealthy states, with one exception: The Pacific Island nations, which have experienced disproportionately high rates of obesity. Between 1980 and 2008, two Pacific Island nations, Nauru and the Cook Islands, had rates of increasing BMI at over four times higher than the global mean.
These extreme rates are rooted in colonial history, which altered Islander’s cultural and lifestyle practices. Both states were colonized in the late 19th century and gained independence in the 1960s. Traditionally, Pacific Island nations earned income and food from farming and fishing. However, Western pressure to prioritize productivity-based economic growth led Islanders to trade their traditional diet for one based on convenient, imported food. Their new diet was processed and low in nutritional value, high in refined flour, sugars, and preservatives to ensure a long shelf life. In addition, colonizers introduced methods such as cooking and frying food, practices which diverged from a traditionally raw diet and further decreased nutritional value. Moreover, this shift away from farming and finishing toward office-based employment reduced the daily physical activity once built into their lives.
In contrast, Sub-Saharan Africa and South Asia have yet to experience a significant rise in obesity. Lower levels of industrialization and urbanization, combined with widespread poverty, food insecurity, and malnutrition, keep obesity rates relatively low. In these regions, health issues and disease are often characterized by stunting and wasting, rather than excess weight. Here, the problem isn’t food quality, but food scarcity.
Recognizing the urgency of this crisis, global and local initiatives have emerged to promote healthier environments. The 2025 Partnership for Healthy Cities Summit brought together mayors and officials from 61 cities around the world to share strategies for reducing preventable non-communicable diseases.
During the summit, Córdoba, Argentina, proposed an obesity-busting school lunch initiative—an approach which has since led to meaningful systematic change. Through a municipal decree, the city first limited the sale of sugary drinks and plans to restrict all sugary foods. The initiative is supported by campaigns such as “Córdoba Chooses Water”, which aims to promote hydration by installing public water fountains and educating citizens on the negative effects of sugary drinks.
Overall, the global rise in obesity signifies a larger shift in disease—from communicable to non-communicable. As non-communicable diseases increasingly affect countries across income levels, global health systems and policies must evolve to address these complex, interconnected challenges. Combating obesity requires more than lifestyle change, but systematic change that embeds health equity into global policies.
Edited by Adele Torrington
Featured image: Photo by Kenny Eliason is licensed under the Unsplash License.
