Malnutrition: the stunting that mortgages the future

There is a form of malnutrition that cannot be seen. The child does not look ill, does not lose weight dramatically, simply grows more slowly than it should, and forever. This is stunting, and it today affects 150.2 million children under the age of five worldwide, or 23.2 % of that age group (JME 2025). West Africa concentrates a disproportionate share of it: roughly one child in three is affected there, up to 47.7 % in Niger. This is not just one health statistic among others. It is an amputation of human capital that is decided before the child's second birthday, becomes irreversible once that milestone has passed, and is then paid for over an entire lifetime, in learning, in earnings and in national growth. The question is not whether the region can defeat this scourge, others have done so, but whether it decides to measure where it strikes in order to fight it there.

One of the hardest-hit regions, yet with staggering internal gaps

West Africa remains one of the most affected sub-regions on the planet. The average prevalence of stunting there is close to one child in three, well above the global average of 23.2 % (JME 2025). But behind this regional finding lies a striking dispersion. Niger peaks at 47.7 % (2022), the highest rate among the nine reference countries, while Ghana (17.4 %) and Senegal (17.5 %) fall below the threshold of one child in five. Between the first and the last, the ratio is nearly one to three. Benin, at 34.1 % (2021), ranks among the leading high-prevalence countries, alongside Nigeria (33.8 %). In other words, two neighbouring countries can show rates ranging from one to three under comparable climates and soils. This hierarchy does not tell a story of geographic fate: it tells a story of nutrition and public health policy choices.

The silence of stunting: why it escapes attention for so long

Childhood malnutrition has three faces, and they share neither the same visibility nor the same urgency. Wasting, the acute form, can be seen: the child is too thin for its height, is in immediate danger of death, and requires emergency care. Underweight combines both dimensions. Stunting, for its part, means being too short for one's age, and that is precisely what makes it so formidable: a stunted child can appear healthy, play, smile, raise no alarm. The tragedy unfolds quietly, in the tissues and the brain, without any obvious clinical signal. It is this invisibility that delays care and makes stunting the poor relation of emergency policies, even though it is by far the most widespread form.

The thousand days: a narrow window that does not reopen

Everything is decided in the first 1,000 days, from conception to the second birthday. This is the period when the brain and body build themselves fastest, when every deficiency leaves a lasting imprint. Beyond that point, the accumulated deficit becomes largely irreversible: missed growth cannot be caught up the way a learning gap can. This narrow window changes everything for public action. It means that an intervention arriving too late, at five or six years old, repairs nothing. It also means that nutritional investment has an expiry date: the franc spent during pregnancy and the first two years of life yields a return incomparable to the same franc spent later. Targeting the thousand days is not a preference, it is the only strategy that works.

The causes of this stunting are known, and they compound one another. A poor maternal and infant diet, in quantity as in diversity, deprives the child of the nutrients of growth. Repeated infectious diseases (diarrhoea, malaria) divert available energy and destroy nutritional gains. Unsafe water and inadequate sanitation sustain this cycle of infections. None of these factors is inevitable: each can be fought with proven means. But because they act together, they demand a coordinated response, at the crossroads of health, nutrition and access to water, and therefore a steering capacity able to track several levers at once.

Stunting is decided before the second birthday and can no longer be reversed. It is the only health catastrophe whose exact window is known in advance, and which we nonetheless allow to close.

Ghana and Senegal halved their rate: proof by facts

The best antidote to fatalism is the comparison of trajectories. Ghana brought its stunting rate down from 35.5 % in 2003 to 17.4 % in 2022: a halving in one generation. Senegal followed a parallel path, from 26 % in 2000 to 17.5 % in 2023. These two countries show that a rapid and lasting decline is possible, without any technological miracle, through a patient combination of access to primary care, promotion of breastfeeding and young-child feeding, and improved water and sanitation. Conversely, Niger remains anchored above 47 %, and Benin has hovered since 2001 around one third of children, with no trend of progress. The divergence of these curves is explained neither by climate nor even by wealth level alone: it measures the intensity and constancy of the public health effort.

The Beninese case is one of lasting stagnation. Since 2001, the national rate has never durably fallen below the threshold of one child in three: 36.2 % in 2001, 32.2 % in 2018, then a rise back to 34.1 % in 2021. Twenty years without a breakthrough, while comparable neighbours gained eighteen points. This inertia has a cost that does not show up in the year's accounts, but that accumulates silently in a generation of children whose cognitive and productive potential is durably impaired.

What national averages hide: a brutal social divide

A national rate is an average, and averages anaesthetise. Behind Nigeria's 33.8 % lies a divide that should be at the centre of any nutrition policy. According to the 2023-2024 DHS, stunting affects 55.9 % of children in the poorest quintile against only 14.7 % in the wealthiest quintile: a 41-point gap, more than one poor child in two against barely more than one rich child in seven. Benin shows the same divide, from 41.2 % among the poorest to 18.6 % among the richest (DHS 2017-2018). Stunting is not evenly distributed: it is first and foremost a disease of poverty, and the national rate says far too little to guide action.

More troubling still: this divide widens over time. In Nigeria, over twenty years, children in the wealthiest quintile saw their rate fall from 20.2 % (2003) to 14.7 % (2024), while those in the poorest quintile stagnated above 52 %, reaching 55.9 % in 2024. National progress, such as it is, has benefited children who were already advantaged and left the others behind. This is a reminder that economic growth, on its own, does not close the nutritional gap: without explicit targeting of the most exposed populations, it can even widen it.

The cost of inaction: an invisible tax on human capital

Stunting is not only a health tragedy: it is a quantifiable economic drag. At the individual level, it is associated with a reduction in adult earning capacity that can reach 22 %, through the twin channels of fewer years of schooling and diminished cognitive abilities (Population Reference Bureau). A stunted child statistically becomes an adult who learns less, earns less and produces less. At the national level, the Cost of Hunger in Africa study (African Union, ECA, NEPAD, WFP) has quantified these losses: 2.6 billion USD per year in Ghana, or 6.4 % of its GDP, and up to 16.5 % in Ethiopia. At the continental level, a review of the economic literature estimates that stunting may have cut Africa's GDP per capita by around 10 %. These figures vary by method and deserve to be handled with caution, but the order of magnitude is robust: childhood malnutrition costs points of GDP, year after year.

The price of inaction can also be read in the World Bank's Human Capital Index, which measures how much of their productive potential a child born today will attain, health and education included. Niger and Mali post an index of 0.32 out of 1: a child born there will reach only about 32 % of what it could have achieved under optimal health and education conditions. Stunting is one of the roots of this ceiling. It does not only amputate one generation of children: it durably lowers the production frontier of entire countries, and passes the handicap on from one decade to the next.

The poorly targeted budget: spending without reducing

Faced with a problem whose window is known (the thousand days) and whose social geography is known (the poorest households), the most costly mistake is to spend blindly. A nutrition programme that distributes uniformly, without accounting for gaps between quintiles, between regions and between ages, wastes part of its budget on children already out of danger while missing those who need it most. Yet this is precisely what steering based solely on national averages produces. The levers, however, are known and inexpensive: promotion of breastfeeding, micronutrient supplementation, treatment of infections, access to safe water. Their return depends less on their nature than on their targeting. The same budget produces a radically different reduction in stunting depending on whether it targets the areas and ages with wide gaps or whether it sprinkles resources thinly.

• The when. An intervention has value only within the 1,000-day window; targeted at pregnant women and children under 2, it transforms; arriving later, it no longer repairs.
• The who. The 41-point gap between quintiles in Nigeria means that a franc invested in the poorest-quintile households yields far more, in points of stunting averted, than a franc distributed uniformly.
• The where. National averages mask sub-regional pockets of far higher prevalence; without fine-grained mapping, public investment ignores where the need is concentrated.

Wasting: the visible and deadly tip of the iceberg

If stunting is the most widespread form, wasting is the most acute and the most lethal: a child too thin for its height is in immediate life-threatening danger. Nigeria posts the highest rate in the sample (11.6 %), ahead of Niger (10.9 %) and Senegal (10.2 %), with Benin at 8.3 %. These two forms of malnutrition are not opposed, they often coexist in the same child and in the same households, and they share deep-rooted causes: poverty, food insecurity, infectious diseases. A serious nutrition policy therefore cannot treat the emergency of wasting without tackling, upstream and over time, the soil that produces stunting. One is treated in weeks, the other is prevented over years; both call for the same data foundation.

Benin facing its own social divide

Benin does not escape the common rule: its national average of 34.1 % conceals separate worlds. The 2017-2018 DHS shows a clear gradient, from 41.2 % of stunting among children in the poorest quintile to 18.6 % among those in the wealthiest, a gap of more than twenty points. A Beninese child born into a poor household is more than twice as likely to be stunted as a child born into a well-off household, in the same country, under the same climate, with the same theoretical supply of care. The national stagnation over twenty years is therefore not a homogeneous figure: it is the sum of progress among the most advantaged and of a bogging-down among the most vulnerable. Any strategy that aims to finally move the national rate will have to target first this bottom of the distribution.

A data problem before it is a resource problem

The thread linking all these findings is the same: you cannot effectively fight what you do not measure finely. Stunting is a data problem before it is a resource problem. Knowing who (which quintile, which age), where (which municipality, which neighbourhood) and why (diet, infections, water) is the first condition for targeting the thousand-day window where it matters. Yet national rates, useful for comparing countries, say nothing about the inside of a country. Anthropometric field measurement (height-for-age, weight-for-height, weight-for-age), disaggregated by wealth quintile and geolocated at the subnational scale, is what turns an aggregate figure into an investment roadmap.

This is the conviction that guides CRAD's work in public health. The firm equips the entire chain, from field anthropometric surveys (height-for-age measurement, wealth quintiles, subnational disaggregation) through to monitoring-and-evaluation dashboards that enable states and donors to steer nutritional investment where the human-capital return is greatest. Measuring where stunting strikes, tracking the effect of each programme campaign after campaign, and redirecting resources towards the pockets of highest prevalence: this is how a nutrition policy moves from generous intention to the precision that saves life trajectories.

Fundamentally, stunting is not an unsolved scientific enigma: public health has long known how to prevent it. It is a problem of political constancy and of steering by data. The countries that are making progress, Ghana, Senegal, are those that sustained the effort over a decade and directed it where it was needed. Those that stagnate do not lack solutions: they lack a compass precise enough to aim at the right child, in the right place, at the right time. Closing the nutritional gap means first deciding to measure it, quintile by quintile and municipality by municipality, then never letting go of it during the thousand days that decide everything.

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