Access to variety contributes to dietary diversity in China

Highlights

• Diet diversity increased in rural and urban China during the period 1989–2009.

• Diet diversity grew at a faster pace in urban settings.

• Cost of access generates friction in a consumer’s ability to consume variety.

• Results suggest a role for differentiated food policy in rural and urban China.

Abstract

In the canonical consumer demand problem, an agent makes a decision about quantities to consume, under the assumption that all varieties can be accessed at zero cost. In reality, the cost of accessing variety may not be zero. In this paper we study the effect of variety access cost on the consumption of food variety and its role in explaining regional differences in dietary diversity in China. We find that a higher cost of access negatively affects the individual’s ability to diversify her diet in terms of both the total counts and the balancing of varieties consumed. The primary policy implication of this research is that attempts to create a healthy food environment in China must be differentiated along rural and urban lines. In rural communities where consumers have been limited in their ability to diversify food baskets by high electricity and transportation costs, infrastructure development and modernization may effectively improve nutritional balance. For more urbanized communities where the cost of consuming additional food variety is relatively low, food policies might instead focus on interventions that promote healthy eating to mitigate the burden of over-nutrition.

Introduction

Like many developing countries, China is experiencing a nutrition transition, in which income growth and urbanization begin to shift diets away from coarse grains and legumes towards greater consumption of sugar, edible oil, and animal protein (Popkin, 2014). This shift raises the possibility that China is, or will soon be facing a double disease burden resulting from both under-nutrition among the poor and over-nutrition among the non-poor. The latter is of special concern given the rapid rise over the past two decades in the rates of those in China who are overweight (Gordon-Larsen et al., 2014). Since increases in overweight prevalence will continue to outpace reductions in underweight prevalence (Dearth-Wesley et al., 2007), the focus of food policy in China must evolve from food security to health-related considerations. As a result, nutrition balance and diet diversity will become more relevant dimensions of healthy diets in China, compared with calorie and nutrition adequacy. It is generally thought that an increase in variety brings about nutritional improvements, a view supported by research (e.g. Kant et al., 1993, Lo et al., 2013), but improvements are not guaranteed. Outcomes depend on the choices consumers make, which in turn depend on the choices available to them.

Studies of dietary diversity among Chinese consumers are somewhat rare. Exceptions include Kim et al. (2003) who construct a Diet Quality Index-International (DQI-I) to assess diet quality (including variety) but do not account for regional distinctions, and Li et al. (2009) who compare rural–urban DQI-I but focus on differences among families with and without youth. Liu et al. (2012) investigate urban–rural nutritional disparities, but do not include all categories of food and study the status of children only. Moreover, most of these studies share a common interest in the role of particular household socio-economic characteristics such as income, household size, age, sex composition, employment status, education level of the household head, but do not directly explore the idea that the cost of access to variety and the technology-related cost of seeking and accessing additional variety may be determined by the setting in which consumers make choices. Understanding this is important, since variety due to greater access may have different nutritional and policy implications than variety brought about by increases in income or other demand-side factors. This is a key aspect of the debate in high income countries, where some argue that taxes and restrictions on the food environment are required to improve nutrition (Miljkovic et al., 2008, Kuchler et al., 2005) while others emphasize the importance of consumer education (Freeland-Graves and Nitzke, 2002).

Understanding variety in food consumption is also of economic importance. A diversified diet improves a consumer’s welfare both because greater variety increases the likelihood of matching a consumer’s preferences with product characteristics and because variety counteracts diminishing returns to quantity (Li, 2013). Furthermore, understanding diversification in food demand can be particularly important to understanding the evolution and structure of food marketing systems (Reardon et al., 2003, Pingali, 2007).

In this study we examine regional differences in dietary diversity in China and offer explanations for these differences. Here diversity is measured by both the total number of varieties consumed and the consumption balance in terms of quantity and food categories.³ It is not our objective to measure the relationship between dietary diversity and nutritional outcomes. Instead, we are interested in the question “What could have possibly contributed to the evolution in dietary diversity among Chinese consumers?” When approaching this question, we place a special emphasis on the cost of accessing variety in urban/rural settings and on what this cost implies for strategic attempts to promote healthy diets among Chinese consumers. Our contribution is primarily empirical. Our results suggest that a higher cost of access, driven by lower availability, higher transaction costs of seeking and obtaining variety, and limited access to improved food storage, adds a marginal cost to the market price of variety and creates friction in the individual’s ability to diversify her diet. We also find that this friction is somewhat greater in rural areas, resulting in less diversity. Consuming less variety may or may not imply lower nutrition, but as long as nutritional differences are associated with differences in diversity, an implication of the result is that the same food and nutrition policies many not apply equally to rural and urban China.