By 2040 there will be more children who are overweight than not for the first time in history, a new report has found. Childhood obesity is rising worldwide and will reach 228 million by 2040, surpassing for the first time the number of underweight children, according to the latest World Obesity Atlas 2026.

More than 180 countries are experiencing rising rates of childhood overweight and obesity, with the fastest growth occurring in low- and middle-income countries where most of the world’s children live, claims the report, which is published by the World Obesity Federation.

In 2025, there were 177 million children between the ages of five and 19 living with obesity worldwide, a number expected to reach 228 million in 2040 – the equivalent of a rise from 8.7 percent to 11.9 percent of the world’s children and adolescents.

The authors noted that the speed at which these numbers are increasing makes this trend “particularly alarming”.

Where are the highest obesity rates?

Policy change will also need to reflect the geographic shifts in obesity prevalence. It is no longer the case that high-income countries have the highest rates, with numbers rising in upper-middle-income countries, and the highest prevalences will continue to be seen in the Americas, the Eastern Mediterranean region, and the Western Pacific.

Why is obesity rising?

The report noted that the risk of developing overweight in childhood is increased by multiple known factors, including the health and habits of mothers, early nutrition, and inadequate physical activity.

Key factors include maternal overweight and obesity, diabetes, and smoking, as well as insufficient breastfeeding during the first months of life, the quality of school meals, and low physical activity.

What are the consequences of childhood obesity?

Overweight and obesity during childhood not only increase the risk of chronic diseases later in life, but they also pose risks in the early years, when healthy development is critical.

Childhood obesity is a known predictor of obesity and other chronic diseases, such as heart disease and cancer, in adulthood.

However, signs of these chronic diseases can already appear during childhood. By 2040, at least 120 million school-age children are expected to have early signs of chronic disease caused by high Body Mass Index (BMI), according to the report.

Several indicators of early chronic disease can be linked to unhealthy weight, such as liver disorders, high triglycerides (a risk factor for cardiovascular disease), hyperglycaemia (a risk factor for diabetes), and hypertension (a risk factor for stroke).

Childhood and adolescent obesity also carry adverse psychosocial consequences, affecting school performance and quality of life, complicated by stigma, discrimination and bullying, according to the World Health Organization (WHO).

What’s the way forward?

Prevention policies alone will not be sufficient, the report noted. The World Obesity Federation is calling for stronger health, food, school, and built-environment policies, alongside equitable access to care and nutritious food for all children.