درباره اقتصاد خرد مواد غذایی و سوء تغذیه تحت تنزیل درون زا
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|5875||2013||17 صفحه PDF||سفارش دهید||14100 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : European Economic Review, Volume 59, April 2013, Pages 80–96
This paper explores the microeconomics and dynamics of food and nutrition. It examines the linkages between malnutrition and the incentive to invest and accumulate capital. The analysis focuses on a dynamic model where preferences about the future depend on nutrition and health. Situations of malnutrition cover both ends of the spectrum: from nutrient deficiency to obesity. The model involves preferences that are not time-additive and exhibit endogenous discounting. This provides a framework to investigate the factors affecting consumption and investment behavior. The adverse investment incentives of malnutrition are examined.
Malnutrition has always been a subject of concern. It covers both ends of the spectrum, going from undernutrition associated with nutrient deficiencies to overnutrition associated with obesity problems. Much research has been conducted on the economics of hunger and nutrient deficiency. It is well understood that chronic hunger results from extreme poverty when the income of poor households is too low to support an adequate diet. FAO has estimated that the number of undernourished in the world exceeds 800 million people (FAO, 2009). And 160 million people live in ultra poverty on less than 50 cents a day (Ahmed et al., 2007). In extreme situations, the purchasing power of the poor is below a minimal subsistence level, leading to starvation and death (e.g., Glomm and Palumbo, 1993 and Sen, 1981). In less extreme situations, poverty can lead to insufficient food intake and nutrient deficiencies (including energy, proteins as well as micronutrients), with adverse effects on productivity and welfare (e.g., Dasgupta and Ray, 1986, Strauss and Thomas, 1998 and Wheeler, 1980). Even if aggregate food production is sufficient to provide an adequate diet to every human on earth (e.g., Runge et al., 2003 and Sachs, 2005), undernutrition problems persist especially in developing countries. At the other extreme, malnutrition can come from excessive food intakes leading to obesity and health problems. Obesity issues are found in every country and are becoming more severe. The World Health Organization calls obesity a “global epidemic.” In the USA, the incidence of obesity has increased sharply over the last twenty years. More than 34 percent of U.S. adults are now obese; and the number of overweight children has doubled in the last decade (Anderson et al., 2003 and Centers for Disease Control, 2010). Persons who are overweight face a higher risk of certain diseases (e.g., heart disease, high blood pressure, diabetes) and a loss of wages and productivity (e.g., Wada and Tekin, 2010). It has been estimated that the annual cost of obesity and overweight in the USA exceeds $100 billion (Finkelstein et al., 2003 and Wolf and Colditz, 1998). Understanding malnutrition requires understanding food consumption behavior. The effects of prices and income on food consumption have been studied extensively. It is well understood that there is a minimal purchasing power below which a household cannot support an adequate diet for its members (e.g., Dasgupta and Ray, 1986, Glomm and Palumbo, 1993, Sen, 1981 and Wheeler, 1980). It means that insufficient income is an important cause of hunger and undernutrition. However, while there are clear linkages between the rise in obesity and an increase in calorie intake (Bleich et al., 2008), the causes of overnutrition are complex (Rashad, 2006 and Rosin, 2008). Lakdawalla and Philipson, 2009 have estimated that 40 percent of the recent growth in obesity is due to lowered food prices. This means that remaining 60 percent is due to other factors. These factors include the adoption of more sedentary lifestyle and a reduction in physical activities and calorie expenditures. Some have argued that an increased reliance on food away from home and fast food are also a contributing factor (Chou et al., 2004 and Guthrie et al., 2002). Yet, it is not clear whether more “eating out” is a causal factor since restaurants can cook low-calorie food as easily as high-calorie food (Cutler et al., 2003). Finally, obese individuals are found in every socio-demographic group and at every income level (Centers for Disease Control, 2010, Richards and Patterson, 2006, Sundquist and Johansson, 1998, World Health Organization, 2000 and Zhang and Wang, 2004). How can we explain the presence of malnutrition among the poor as well as the non-poor? Rational individuals decide how much food to consume on the basis of tastes, prices and income, accounting for the anticipated future health consequences of their actions. Many factors play a role, including genetics, nutritional education, information as well as lifestyle. In general, weight control requires one to forego current consumption in order to gain future potential health benefits. Since there is extensive information on the relationship between health and nutrition, this suggests that individuals who become obese exhibit a high degree of “impatience”, their time preferences giving much more weight on the short-term reward of current food consumption compared to its longer-term health effect (Borghans and Golsteyn, 2006). This indicates that obesity is associated with heavy discounting of the future (Becker and Mulligan, 1997, Ehrlich and Chuma, 1990, Fuchs, 1991, Komlos et al., 2004, Smith et al., 2005 and Zhang and Rashad, 2007). This paper argues that heavy discounting of the future is a basic characteristic of malnutrition, including both overnutrition and undernutrition. To see that the argument applies to undernutrition, it suffices to note that starving individuals are not expected to be concerned about their longer-term future when starvation means imminent death. This means that hunger and starvation are expected to be associated with heavy discounting of the future. But such arguments lose their credibility under adequate nutrition. It means that the discounting of the future varies with the nutritional status of individuals. This creates a fundamental challenge to the standard economic model where discounting the future is typically done at a constant rate (e.g., Deaton and Muellbauer, 1980; Samuelson, 1928). It indicates a need to consider situations where time discounting is endogenous (as it varies with nutrition) and examine its implications for individual behavior. Note that the argument that time discounting varies over time and across individuals is not new (e.g., Frederick et al., 2002). What is new in our analysis is the linkage between nutrition and time preferences. Our main contribution is to investigate the implications of such a linkage for individual behavior, investment incentives and capital accumulation. Like Becker and Mulligan (1997), our purpose in not to make ethical judgments about human decisions; rather it is to refine our understanding of individual behavior related to nutrition. This paper takes a new look at the microeconomics of food consumption and nutrition. Consumer theory provides the foundation of the economics of food demand, especially the analysis of price and income effects in consumer behavior (e.g., Deaton and Muellbauer, 1980). Typically, the analysis is presented at the household level treated as the basic unit for decision making. Yet, nutritional status is an individual characteristic (e.g., nutritional achievements can vary among individuals within a household). This means that our analysis of the economics of nutrition is developed at the individual level. We develop a dynamic microeconomic model of an individual making consumption/investment decisions over time. Building on the strong relationships existing between food consumption, nutrition and health,2 we link the nutritional status of the individual with the way he/she discounts the future. As discussed above, we associate heavy discounting of the future with situations of significant malnutrition (either undernutrition or overnutrition). Arguing that time discounting varies with current food consumption, we challenge the adequacy of standard economic models that treat discounting as exogenous. This is done by developing a dynamic model under recursive (non-additive) preferences allowing for endogenous discounting. Associating malnutrition with heavy discounting of the future, we explore the implications for consumption and investment behavior. We demonstrate that nutritional considerations contribute to the concavity of the Engel curve (relating consumption with income). We show that obesity leads to a more inelastic consumer demand at least in the short run. This indicates that, under a highly-inelastic food demand, a tax on high-calorie food may have limited effectiveness in reducing obesity. We also document how the behavioral effects of risk vary with individual nutritional status. In general, we argue that the effects of malnutrition go beyond the short-term effects of malnutrition on labor productivity. In particular, we investigate the linkages between malnutrition and the incentive to invest and accumulate capital. We show that, under hunger, endogenous discounting contributes to reducing the incentive to invest. Since accumulations of physical and human capital are a crucial part of the process of economic growth, our analysis provides new insights into the relationships between nutrition, investment and economic development. Through the disincentive to invest, we argue that undernutrition and hunger can contribute to a poverty trap,3 where prospects for capital accumulation and economic growth are poor. Economic and policy implications are discussed.
نتیجه گیری انگلیسی
We have explored the microeconomic linkages between food demand, nutrition, investment and capital formation. A key aspect of the arguments relates to how malnutrition (including both undernutrition and overnutrition) can have adverse effects on investment incentives. These effects are captured in the context of non-additive preferences where the discount factor (reflecting time preferences) is endogenous and depends on food intake. This gives useful insights on how food consumption affects investment incentives and capital accumulation. While the standard time additive model may be appropriate for well-nourished individuals, it appears inappropriate in situations of malnutrition (involving either nutrient deficiencies or obesity). Under malnutrition, we explored the implications of endogenous discounting for consumption and investment behavior. In this context, we analyzed the effects of income, prices, risk and initial capital on consumption and investment behavior. We investigated how economic behavior can vary with the nutritional status of individuals. And we explored the implications of our results for economic policy. For example, we found that hunger can strengthen the positive effects of income on consumption, thus weakening the incentive to invest. We also found that obesity contributes to the price inelasticity of consumer demand. This reduces the effectiveness that a tax on fat or high-calorie food would have as a means to combat the obesity epidemic. Our research examined the linkages between nutrition and food demand, with implications for investment behavior. Our analysis points to issues that need further refinements. First, empirical analyses are needed to explore the nutrition-investment linkages identified in this paper, especially the effects of food and income transfers on economic growth. In the presence of significant heterogeneity across consumers, this stresses the need to rely on micro-level panel data in the dynamic investigation of malnutrition issues. Second, the role of nutritional education and its effects on behavior need further investigations. Third, the linkages between life cycle, nutrition and consumption behavior are worth further examination, especially the factors affecting the diet of infants and children. Finally, our analysis has focused on food and nutrition. There is a need to refine our understanding of broader linkages between individual behavior, life-style patterns and health.