The research, published in the journal Food Policy by a team spanning the Alliance of Bioversity International and CIAT, Cornell University, the Global Alliance for Improved Nutrition, Purdue University, the Kula Vyema Centre of Food Economics, and collaborators at several other institutions, is a systematic scoping review of extraordinary scale. The team screened 23,250 records and analyzed 327 studies from 64 countries published since 2000. Their questions were deceptively simple: How is informality defined and studied in food environments? What do we know about its links to nutrition and food choice? And what sociopolitical and livelihood factors shape the people who do this work? The answers, it turns out, reveal a field in disarray — and a policy apparatus built on shaky conceptual ground.

The most striking finding is definitional. Fewer than a quarter of the studies reviewed clearly specified what they meant by “informal,” and among those that did, definitions varied wildly. Some anchored informality in location, some in licensing status, some in whether a vendor had a physical stall. That may sound like academic hair-splitting, but the consequences are concrete. A location-based definition leads to place-based policy. An infrastructure-based definition leads to market upgrades. A licensing-based definition leads to formalization drives — campaigns to register and regulate vendors — which have mostly failed in practice because the costs of registration and compliance are rarely designed around how informal work actually functions. As market and community development specialist Mark Lundy of the Alliance of Bioversity International and CIAT put it, the choice of definition “induces certain policy conclusions before the data comes in.”

Lundy also emphasized a blind spot with real regulatory stakes. Informal vendors supply fruits, vegetables, and animal-source foods alongside ultra-processed products, so regulation aimed at one side lands on the other. Agricultural economist Simon Kimenju of the Kula Vyema Centre echoed the point: informal food vendors are not only conduits for nutrient-dense foods but also major outlets for ultra-processed foods in both rural and urban areas. Research on ultra-processed foods, he argued, needs to include informal food environments alongside formal markets — harder to regulate, but unavoidable if governments want policies that actually reach the food people eat.

Gender runs through nearly every strand of the evidence. Women make up the majority of informal food vendors, and the review documented gender-specific patterns in who sells what, where, and under what constraints — from spatial segregation in fish markets to outright exclusion from public space and credit. One of the most vivid examples comes from Dhaka, where researchers documented vendors using what scholars call “quiet encroachment”: when police approached, male vendors would duck under tea tables while their wives took over the stall, because officers were reluctant to arrest women. It is a small, telling illustration of how informal actors navigate, and are shaped by, the sociopolitical realities around them.

Yet the gender findings contain a gap inside themselves. Lundy noted that bribery, harassment, and personal safety are barely studied, and that women are well documented as subjects of policy but far less as agents in it. Public health nutritionist Swetha Manohar of the International Food Policy Research Institute added that gender is a critical but not the only axis of inequality: vendors cluster in poor communities such as informal settlements and areas near low-wage workplaces, so inequality is about where selling happens as much as who sells. Migration status also shapes women’s paths into vending, though it remains understudied — a gap that will likely grow more urgent as climate pressures reshape human movement.

Beneath the economics lies something researchers call “social infrastructure”: the web of informal relationships that stabilizes supply chains, shares risk, and confers legitimacy on work that has none on paper. Informal food environments run on trust and reciprocity, not just transactions. Nutritionist Elizabeth Fox of Cornell University argued that this complexity demands a multidimensional understanding of informality. The widely used International Labour Organization definition, she noted, captures only a limited set of dimensions; infrastructure, types of products sold, spatial characteristics, and visibility are all highly relevant to how informal food systems operate in practice. Without that nuance, she warned, researchers risk “reducing complex social and economic practices to overly narrow categories that obscure the people behind them.”

The evidence base itself has structural weaknesses. Public health nutritionist and statistician Nilupa Gunaratna of Purdue University pointed out that most research has been cross-sectional, capturing vendors at a single point in time even though informal work is precarious and vendors constantly adapt without safety nets. Space matters too: urbanization is proceeding not only in capital cities but in smaller cities and peri-urban and rural areas, where little research has looked. There is also a striking absence of data on vendors’ own health and nutritional well-being — the people who facilitate access to healthy diets cannot be identified, measured, or compared across studies without first agreeing on who they are. Sociologist Rachel Bezner Kerr of Cornell University added that the link between informal vendors and health, diets, and nutrition outcomes is understudied, in stark contrast to the many studies connecting smallholder farm production to household nutrition, and that workplace dynamics such as childcare, migration, and bribery remain under-explored.

For policymakers, the review’s most actionable message comes from the 214 studies that offered recommendations across more than 40 countries. The clearest and most consistent advice was to move beyond the formal/informal binary altogether. Basic infrastructure — water, electricity, designated vending zones, cold storage — was the single most common recommendation, followed by gender-responsive financial inclusion and social protections for informal workers. Avery Sirwatka of Cornell University observed that formalization efforts have largely failed in part because registration, licensing, permitting, and food safety compliance costs are rarely designed with local informal work conditions in mind; the literature instead points toward collaborative governance models and legal recognition of vendors’ economic roles as approaches better suited to meeting both vendor and social needs.

The researchers are candid that ambiguity itself is a policy problem. Agri-food system sociologist Jenny Wiegel of the Alliance of Bioversity International and CIAT noted that unclear classification limits the ability to compare across contexts, generalize into theory, or even conduct coherent policy debates. Nutrition epidemiologist Ramya Ambikapathi, the review’s lead voice, reflected that informal spaces are inherently contested — sites of rich biodiversity and traditional foods but also of illegal bushmeat, main sources of vegetables in some contexts and doorstep delivery of ultra-processed foods in others, sustained by genuine demand because formal food systems leave out most of the population in low- and middle-income countries. Human geographer Jane Battersby of the University of Cape Town found the rapid growth in publications on informality encouraging, and hopes it will translate into governance that supports the sector. Agricultural economist Stella Nordhagen of GAIN said the sheer diversity of how informality was defined and conceptualized — even among the paper’s own coauthors — underscored both the importance of informal actors and the complexity of studying them. The paper, “Informality in Food Environments: A Systematic Review of Nutrition, Livelihood, and Sociopolitical Outcomes and Implications for Food Policy,” is now in press at Food Policy, and its conclusion is hard to escape: informality sits on a continuum, not in a binary, and policy that ignores that will keep missing the people who feed a large share of the world’s poor and urban populations.

Subject of Research: Informality in food environments and its nutrition, livelihood, and policy implications in low- and middle-income countries

Article Title: The invisible backbone of the world's food system: What 327 studies from 64 countries tell us about informal food vendors

Article References: The invisible backbone of the world's food system: What 327 studies from 64 countries tell us about informal food vendors. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: informal food vendors, food environments, food policy, food security, systematic review, gender, low- and middle-income countries, street vending, ultra-processed foods, livelihoods, urbanization, social infrastructure

The research, conducted by Rishika Raj and Bimal Kishore Sahoo, tackles a question that sits at the heart of food security policy: what happens to the quality of people’s diets when the societies they live in undergo rapid structural transformation? Food security is conventionally understood through several dimensions, including availability, access and utilisation. Dietary diversity, meaning the range of distinct food groups a household consumes, is widely used by nutrition scientists as a proxy for the utilisation and quality dimensions. A household that eats only rice and lentils may consume enough calories, but it misses the micronutrients, proteins and fats that come from fruits, vegetables, dairy, eggs, meat and other foods. Measuring diversity therefore offers a window into nutritional stability that calorie counts alone cannot provide.

What makes this study methodologically distinctive is the way it measures urbanisation. Rather than relying on a single administrative definition, the authors constructed a composite picture of urbanisation using three complementary dimensions. The first is economic urbanisation, captured through night-time lights, the glow that satellites record over human settlements and which economists have long used as a proxy for economic activity and electrification. The second is physical urbanisation, measured as built-up area, the actual footprint of concrete and asphalt that expands as towns grow. The third is demographic urbanisation, the share of a district’s population living in urban areas. Combining these dimensions allows the researchers to distinguish between districts that are merely administratively urban and those experiencing genuine economic and physical transformation.

On the dietary side, the authors drew on household consumption expenditure data to construct a dietary diversity score using Simpson’s Diversity Index, a measure borrowed from ecology that accounts both for the number of distinct food categories consumed and for how evenly expenditure is spread across them. A household spending heavily on one staple while buying only token amounts of other foods will score lower than one spreading its food budget across many categories. The analysis used district-level panel data spanning 2014 to 2020, allowing the researchers to track how rural and urban dietary diversity evolved together across hundreds of Indian districts over six years, a period that includes the disruptive years of the COVID-19 pandemic.

The headline result is stark: significant and persistent rural-urban disparities in dietary diversity exist across Indian districts, indicating that access to diverse and nutritious diets remains deeply unequal between countryside and city. Urban households, on average, consume a wider variety of foods than their rural counterparts, and this gap does not disappear over the study period. The finding matters because dietary diversity is not a luxury indicator; it is closely tied to micronutrient adequacy and long-term health outcomes. Persistent gaps suggest that the structural transformation pulling people into cities has not yet delivered equal nutritional quality to those left behind in rural areas, where agricultural households may still depend heavily on starchy staples and locally produced foods.

Yet the more provocative finding concerns what happens over time within urban areas. In the short run, the study finds, urbanisation is associated with improvements in dietary diversity for both rural and urban households. As districts urbanise, markets deepen, supply chains lengthen, incomes rise and consumers gain access to a broader basket of foods. This is the familiar, optimistic story of development. But the long-run picture inverts. The analysis reveals that higher levels of urbanisation are linked to declining dietary diversity among urban households, pointing to emerging risks to diet quality and nutritional stability precisely in the places where one would least expect them.

The authors interpret this as evidence of a non-linear and dynamic relationship between urbanisation and the nutritional dimension of food security. Several mechanisms could plausibly explain such a pattern, and the study’s framing points toward the transformation of food environments in dense cities. As urban areas mature, food systems may shift toward processed, convenience-oriented and calorie-dense products that crowd out fresh and varied foods, particularly for lower-income urban households facing high housing costs and time pressures. Urban diets may also become more monotonous as reliance on purchased foods replaces the seasonal variety that local and home production once provided. The study does not claim to identify a single causal mechanism, but its econometric results are consistent with the idea that the early gains from urban food markets eventually plateau and reverse for city dwellers.

The temporal dynamics of the rural-urban gap add another layer of nuance. The researchers found that urbanisation initially widens the divide in dietary diversity between rural and urban areas, as the benefits of urban food markets accrue first to city residents. Over time, however, these gaps narrow. This convergence is not necessarily good news for cities; the study’s long-run results suggest that part of the narrowing may reflect urban dietary diversity declining rather than rural diets catching up. For policymakers, this distinction is critical. A narrowing gap driven by rural improvement would represent genuine progress in food security, whereas convergence driven by urban decline would signal a broad deterioration in diet quality with serious public health implications.

Technically, the study’s use of panel econometrics across Indian districts gives it unusual analytical reach. By examining both short-run and long-run effects, the authors move beyond the static snapshots that dominate much of the food security literature. The use of night-time lights as an urbanisation proxy is particularly valuable in the Indian context, where administrative boundaries and official urban classifications can lag behind the reality of sprawling, economically integrated settlements. Satellite-observed luminosity captures economic dynamism wherever it occurs, including in peri-urban areas that census categories may miss. Pairing this with built-up land data and population shares creates a robustness that single-measure studies lack, and the Simpson’s Index approach to dietary diversity ensures that the food-side measure is sensitive to both variety and balance in household consumption.

The broader implications extend well beyond India. The country is home to hundreds of millions of people undergoing precisely the kind of structural transformation that much of the developing world is experiencing or will soon face. If urbanisation in India follows a trajectory in which early dietary gains give way to long-run erosion among urban households, other rapidly urbanising nations may confront similar dynamics. The authors argue that urbanisation should be viewed not only as a driver of economic growth but also as a process that reshapes food environments and the stability of access to nutritious diets. That reframing has concrete policy consequences: urban food policy cannot assume that market access alone guarantees diet quality, and rural development strategies must address the persistent diversity gap that leaves countryside households with narrower food baskets. As India’s cities continue to swell, the study suggests that the next frontier of food security will be fought not in the fields, but in the streets, markets and households of the cities themselves.

Subject of Research: The relationship between urbanisation and rural-urban differences in household dietary diversity across Indian districts

Article Title: Urbanisation and the rural urban dietary diversity divide across districts in India

Article References: Urbanisation and the rural urban dietary diversity divide across districts in India. (n.d.). https://doi.org/10.1007/s43621-026-04809-y

Image Credits: AI Generated

DOI: 10.1007/s43621-026-04809-y

Keywords: urbanisation, dietary diversity, food security, India, rural-urban gap, night-time lights, Simpson's Diversity Index, district-level panel data, nutrition, Discover Sustainability, food environments, structural transformation