Dietary Choices and Income Inequality: Evidence from Household Food Purchase Data

飲食選擇與所得不均：運用家庭食品購買資料之實證研究

Inequality has become one of the most renowned features of capitalism. This paper focuses on the association between income inequality and people's dietary choices by documenting the differences in dietary patterns between metro markets and their connection to food consumption and income distributions. This empirical study uses a U.S. multi-market household food purchase data set to examine the influence of socioeconomic and demographic factors on health-related dietary choices of salt-sugar-fat intake, organic, vegetable, alcohol and tobacco use. Regression results show that health awareness, ability to pay, price, shopping pattern, and market environment are key to affect individual dietary choice. The effects of income on diet are found not only at the individual level, but also through aggregate income per capita and the degree of inequality. This study provides useful insights for understanding the rationales behind complex dietary behavioral decisions and their distributional differences. Inequalities and dietary choice have important welfare meanings to all societies, not just the United States but also Taiwan or other countries. This study uses a large-scale and comprehensive transactional data which makes it possible to demonstrate how to decompose household food purchase records for further understanding of the association between dietary choice and income inequality. With the approach and insights learned from the case of the U.S., policy makers can utilize the information of income distribution and its potential associations with individual healthrelated dietary choices to design relevant public health policy or nutritional subsidy program.

分配不均是資本主義的特徵及重要的社會問題。本文針對所得不均與 家戶的飲食選擇之關聯進行研究，深入比較美國主要的都會城市的飲食模 式差異、以及與食品消費和所得分配之間的關聯性。本實證研究使用一個 涵蓋數個市場的美國家戶食品購買資料，來檢驗社經和人口因素、購物習 性及所得變數對健康相關的飲食選擇，如低鹽、低糖、低脂飲食、有機食 品、蔬菜、酒及香煙草等之影響。本研究之迴歸結果顯示，對健康的意識 度、支付能力、價格、購物習性和市場環境等因素，是影響個人飲食選擇 的關鍵。不僅個人所得對其飲食選擇有顯著影響，總體層面的所得分配， 包含每人平均所得和所得不均度，也有關鍵解釋能力。這些結果幫助我們 進一步了解複雜的飲食選擇決策，及其與所得分配的關聯。 所得不均和飲食選擇在各個社會都有重要的福利意義，不僅是本研究 所分析的美國，對於台灣或其他國家均具參考價值。本研究利用巨量家戶 實際購買交易資料，提供了一個分析家戶食品購買資料的方法，以從中了 解飲食選擇與所得不均的關聯。這些結論可以提供公共政策的決策參考， 利用所得分配的資訊及其與健康相關的飲食選擇之關聯，用以設計相關的 公共衛生政策或營養補貼計畫。