By Dr SAMUEL HARRISON

In schools and clinics across Nigeria, children are weighed and measured every day. Most families think little of it — a routine number, noted and forgotten. Yet the World Obesity Federation’s latest global data demand that parents, teachers and policymakers look more carefully at what those numbers are beginning to say.

A health crisis Is developing quietly among our children. It is not a future risk. For millions of Nigerian children, it is already here.

A World Transformed by Obesity

Childhood overweight and obesity are no longer problems confined to wealthy nations. They are a global emergency, and the World Obesity Atlas 2026, published on World Obesity Day, documents the scale with figures that are difficult to dismiss.

In 2025, an estimated 419 million children and adolescents aged five to nineteen were living with overweight or obesity worldwide — roughly one in every five children alive today. Global prevalence climbed from 14.6% in 2010 to 20.7% in 2025. Of those 419 million, approximately 177 million meet the obesity threshold. Without decisive action, the Atlas projects that the total will reach 507 million by 2040, more than one in four children on earth.

The consequences are already visible inside children’s bodies. The Atlas projects that at least 120 million school-age children worldwide will be showing early signs of chronic disease — hypertension, cardiovascular risk, metabolic liver disease — attributable to high BMI by 2040. These are conditions that clinicians rarely expected to encounter in children. They are no longer rare.

A generation ago, the dominant health concerns in low- and middle-income countries were infectious diseases and undernutrition. Today, overweight and obesity have emerged alongside persistent undernutrition — a double burden of disease that stretches health systems already under strain.

Where Nigeria Stands

The countries with the highest proportion of overweight and obese children are concentrated in the Pacific and the Americas. Niue leads globally at 66.6% of school-age children, followed by the Cook Islands at 65.5% and Chile at 61.1%. Ten countries now have more than half their school-age children living with high BMI.

By prevalence rates, Nigeria is not among the worst affected. But prevalence figures can mislead. Smaller populations produce dramatic percentages while representing relatively few children in total. When the actual number of affected children is counted — shaped by population size and the pace of Nigeria’s nutritional and economic transition — a very different picture emerges.

According to the Nigeria country scorecard in the Atlas, approximately nine million Nigerian children aged 5 to 19 were living with high BMI in 2025. Of these, around four million meet the criteria for obesity. These figures place Nigeria ninth in the world by absolute number of affected children, a direct result of its large, youthful population.

Unlike high-income countries that have been addressing rising childhood obesity for decades, Nigeria confronts this challenge while still managing undernutrition and infectious disease — a combination that demands responses many health facilities are not yet organised to deliver.

What Is Already Happening Inside Children’s Bodies

The Atlas does not stop at counting overweight children. It estimates how many are already developing early markers of chronic disease, giving health workers and policymakers a window into damage that most systems have not yet organised themselves to see.

Among Nigerian children aged 5 to 19 in 2025, an estimated two million have metabolic dysfunction-associated steatotic liver disease — a form of early liver damage directly linked to excess body weight. Around 975,000 have elevated triglycerides, an early marker of cardiovascular risk. Approximately 702,000 children have high blood pressure. Over 300,000 children show early signs of hyperglycaemia (high blood sugar), which can lead to type 2 diabetes.

These are not projections for some distant adulthood. These are children in Nigerian primary and secondary schools and in community clinics today, carrying metabolic conditions that will shorten their lives if they go undetected and untreated. Children living with obesity are frequently invisible to the health system until complications have already set in. That is the core reason to act now.

What Is Driving the Rise

The causes are recognisable. Rapid urbanisation has removed much of the physical activity that was once part of ordinary daily life — walking to school, outdoor play, farm work. Sedentary behaviour, reinforced by screen time and motorised transport, now shapes childhood in ways that were uncommon a generation ago.

The food environment has shifted just as sharply. Nigerian markets and neighbourhoods are increasingly filled with affordable, energy-dense processed foods and sugar-sweetened beverages. Long working hours in urban households mean convenience frequently outweighs nutritional considerations.

Infant feeding practices carry consequences that extend well beyond infancy. Sub-optimal exclusive breastfeeding in early life is a known risk factor for overweight in childhood. The Atlas reports that most countries experience high levels of sub-optimal breastfeeding exposure — defined as non-exclusive or discontinued breastfeeding before six months — and Nigeria is among them.

There is also an intergenerational dimension. Children born to mothers living with overweight, obesity or gestational diabetes face a higher probability of developing these conditions themselves. Addressing excess weight in women of childbearing age is therefore not a separate issue from child health — it is the same issue.

Progress and Gaps in Nigeria’s Policy Response

The Atlas benchmarks each country against key policy indicators for child protection. Nigeria’s record is mixed, with genuine progress in some areas and real gaps in others.

On implementation of the International Code of Marketing of Breast-milk Substitutes — which measures how well national legislation protects families from aggressive infant-formula marketing — Nigeria scores 84 out of 100. That is a creditable result and reflects regulatory effort that deserves continued enforcement.

Elsewhere, the picture is weaker. National physical activity guidelines for children aged 5 to 19 are not fully established. School food nutrition standards, which govern what children eat during the school day, remain inadequate or poorly enforced. Childhood obesity monitoring, screening and treatment services are substantially lacking. Without structured physical activity programmes and enforceable school nutrition standards, prevention efforts stay fragmented and ineffective. These are not minor gaps. They are structural failures in the environments where children spend their most formative years.

What Must Be Done Now

Nigeria has a window to act before the burden deepens further. That window is narrowing. Four priorities emerge clearly from the World Obesity Atlas 2026.

First, strengthen national surveillance. Growth monitoring and nutrition surveillance must be expanded, standardised and linked to health information systems that can actually guide resource decisions. We cannot manage what we do not consistently measure.

Second, make school nutrition and physical activity standards enforceable. Physical activity should become a compulsory, monitored part of the school day — not left to individual teacher initiative. School food procurement must be governed by binding health and nutrition requirements, not voluntary guidelines.

Third, regulate the food and marketing environment. Stronger regulation is needed to reduce children’s exposure to the marketing[hs1] of unhealthy foods and beverages. Evidence from many countries shows that voluntary industry guidelines do not effectively protect children’s health.

Fourth, integrate screening into primary care. Routine BMI assessment and basic cardiometabolic screening — including blood-pressure measurement — should become standard at every child health consultation. This is where most Nigerian families first encounter the health system, and where early identification is most equitable.

None of these measures requires large new budgets. Most depend on policy reform, better coordination and the consistent enforcement of frameworks that already exist on paper. What they require, above all, is political will and a recognition that childhood obesity is not a lifestyle failure or a parental shortcoming. It is a complex condition shaped by environments that only public policy can meaningfully change.

The Response Cannot Wait

Childhood obesity is no longer a problem of wealthy societies or isolated populations. It is a global health crisis with serious local consequences, and Nigeria — because of its population size and the pace of its nutritional and economic transition — stands at a critical turning point.

The World Obesity Atlas 2026 is unambiguous. Millions of Nigerian children are living with excess weight. Hundreds of thousands already carry early markers of liver disease, cardiovascular risk and metabolic dysfunction. Without deliberate intervention, the path leads toward a generation of adults burdened by preventable chronic disease, reduced productivity and premature death.

The warning signs are not on the horizon. They are written in the bodies of children who have not yet been screened, diagnosed or supported. Nigeria’s policymakers, health professionals, educators and communities have the evidence and the frameworks to act. What remains is the will to move before the consequences become irreversible.

•Dr Samuel Harrison, Chief Medical Officer, member of the Association of Resident Doctors, Federal Capital Territory Administration (FCTA) chapter, based this article on the World Obesity Federation’s “World Obesity Atlas 2026, Childhood Obesity 2nd edition” published in March 2026 and available at: World Obesity Atlas 2026 | World Obesity Federation