The essay that named the problem. Why are South Asian children more undernourished than African children who are poorer? Its answer — the low status, late and poor feeding, and early pregnancies of South Asian women, which produce smaller, weaker babies — set the terms of every debate since. Short, readable, and still the right place to start.
The Stunting Puzzle
South Asia's children are among the most stunted in the world — and richer than many who are taller. A reading list on why, and on what actually brings stunting down.
Stunting — being too short for one's age — sounds like a problem about height. It is not. A stunted child is the visible sign of chronic undernutrition and repeated infection in the first thousand days of life, from conception to a second birthday, when the brain and body are built. The damage done in that window is largely irreversible: stunted children, on average, start school later, learn less, earn less as adults, and are more likely to fall ill. The World Health Organization defines stunting as height-for-age more than two standard deviations below the median of its child growth standards — a single number that compresses a great deal of deprivation.
The puzzle is geographic. For decades, South Asian children have been more stunted than children in sub-Saharan Africa, even though South Asia is, on average, richer and less afflicted by famine and war. In 1996 a trio of UNICEF authors named this the "Asian Enigma" and proposed an answer that still frames the debate: the low status, poor nutrition, and early childbearing of South Asian women, which damages children before they are even born. Later work added a second suspect — the region's exceptional density of open defecation, which spreads the gut infections that stop children absorbing the food they do eat. Neither explanation is the whole story, and the argument between them is part of why this list is worth reading.
There is good news in here too. Bangladesh, poorer than India, drove its stunting rate down faster than almost anyone expected; India's own rate has fallen, if slowly, across successive National Family Health Surveys. The evidence on how — the package of maternal nutrition, breastfeeding, sanitation, women's education, and income that moves the needle — is now reasonably clear, and reducing stunting is among the highest-return investments in all of development. Start with the WHO definition and the Lancet series for the science; read the Asian Enigma and the sanitation work for the live argument; finish with Bangladesh and POSHAN Abhiyaan for what a response looks like.
The Puzzle and the Stakes
Why a measure of height became one of development's most important indicators — and why South Asia's numbers are a genuine puzzle.
The methodological foundation: stunting is height-for-age below minus two standard deviations of the WHO growth standard, built from a multi-country study of how well-nourished children can grow. Understand this and you understand why stunting is comparable across countries — and why it is a measure of a population's conditions, not of genetics.
The paper that made the lifelong stakes undeniable, drawing on five long-running birth cohorts. Stunting in the first two years predicts shorter adult height, less schooling, lower earnings, and — for women — smaller babies in the next generation. The "first 1,000 days" framing comes from here: damage before age two is largely permanent.
Measuring It, Counting It
The data behind the headlines: how many children, where, and whether the numbers are moving.
The authoritative global count of stunting, wasting, and overweight, updated annually and harmonised across countries. Roughly one in five children under five worldwide is stunted, and South Asia carries the single largest share. The source to cite for any cross-country comparison — and the data behind most of the maps you have seen.
India's own benchmark. NFHS-5 puts under-five stunting at about 35.5% nationally — down from 38.4% in NFHS-4 (2015–16), but still more than a third of all children, with wide variation across states and between social groups. Read the state fact sheets alongside the national one; the spread between, say, Kerala and Bihar is much of the story.
The 2013 update to the Lancet series, with the global numbers that anchor the field: undernutrition underlies a large share of all child deaths, and stunting affects scores of millions of children. It also widened the lens to the "double burden" — undernutrition and rising overweight coexisting in the same countries, and sometimes the same households.
The Contested Causes
Maternal status, sanitation, diet, infection — the live argument over what actually keeps South Asian children short.
The most forceful statement of the sanitation hypothesis. Coffey and Spears argue that India's extraordinary rate of open defecation — denser than almost anywhere on earth — spreads the gut infections that prevent children absorbing nutrients, and that caste and notions of purity keep latrines unbuilt or unused. A vivid, evidence-rich, and contested book; read it with the maternal-status argument in mind.
The quantitative backbone of the sanitation case: open-defecation density is statistically associated with a large part of the gap in child height across countries, and helps explain why South Asian children are shorter than their incomes predict. A model of how to argue a causal story with observational data — and of the caveats that come with it.
The counterweight to the sanitation story, though the two are complementary. A large body of work ties child stunting to the mother's own nutrition, body size, education, age at first birth, and autonomy in the household. In South Asia, women often eat last and least; the Asian Enigma's original answer keeps reasserting itself in the data.
Places child undernutrition inside India's broader failure to convert growth into well-being. Drèze and Sen argue that public services — health, sanitation, child nutrition through the ICDS — have lagged far behind incomes, and that this, not poverty alone, explains why so many Indian children remain stunted. The political-economy frame the more clinical studies leave out.
What Actually Works
The evidence on reducing stunting — the proven package, and the country that surprised everyone.
The closest thing to a recipe: a set of proven nutrition-specific interventions — maternal supplementation, breastfeeding promotion, complementary feeding, micronutrients, management of acute malnutrition — that, scaled, would prevent a large share of stunting. Crucially, it also argues these are not enough alone; they need nutrition-sensitive action on sanitation, women, and poverty around them.
The hopeful case. Bangladesh, poorer than India, cut child stunting dramatically over two decades. The IFPRI work decomposes why: rising parental education (especially mothers'), better sanitation, household income, health-service access, and demographic change all contributed — no single magic bullet, but a broad lift across the determinants. Evidence that the number can move fast.
The most recent stocktake: what has changed since 2008 and 2013, where progress has stalled, and how the double burden of under- and over-nutrition complicates the agenda. Essential for an up-to-date picture and for seeing how the field's own thinking has evolved across three Lancet series.
The Policy Response & the Returns
India's national mission, and why economists call reducing stunting one of development's best buys.
India's flagship convergence effort, launched in 2018, which set explicit targets to reduce stunting and brought together the ICDS, health, and sanitation programmes under one mission with technology-enabled monitoring. Read it as the live test of whether the multisectoral package the evidence prescribes can be delivered at the scale of 1.4 billion people.
The cost–benefit case that put nutrition near the top of development's priority lists. Investing in the proven package to reduce stunting yields some of the highest benefit-to-cost ratios in all of development economics — through higher lifetime earnings and lower health costs. The argument that reframed stunting from a humanitarian concern into an economic one.
A good closing reference: UNICEF's conceptual framework organises the causes of undernutrition into immediate (diet, disease), underlying (food, care, environment), and basic (resources, politics) — the map that ties this whole reading list together. Use it to see where each argument above sits, and why no single fix is enough.
ImpactMojo Editorial (2026). "The Stunting Puzzle." ImpactMojo Deep Dives. Retrieved from https://impactmojo.in/DeepDives/the-stunting-puzzle.html
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