We document that within-individual variation in food choices is substantial and has potentially important consequences for nutrition, and hence well-being. We develop an approach that allows us to study the determinants of this within-individual variation within an economic framework and allow for across-individual preference heterogeneity. We show that around one-fifth of within-individual fluctuations in diet quality is explained by standard economic variables (prices and budgets), along with advertising and weather. The residual fluctuations are important and are larger for lower income and younger people, and individuals who state they are impulsive. We propose a two-selves model of food purchase behavior to structurally interpret these empirical patterns. We use nonparametric revealed preference techniques to show that this model rationalizes our food purchase data.
Authors
Rachel Griffith
Rachel is Research Director and Professor at the University of Manchester. She was made a Dame for services to economic policy and education in 2021.
Martin O'Connell
Martin, previously Deputy Research Director, is a Research Fellow at IFS and Professor of Economics at the University of Wisconsin.
Kate Smith
Kate is an IFS Research Fellow and an Assistant Professor at LSE, interested in public finance, industrial organisation and applied microeconomics.
Laurens Cherchye
Laurens is a Research Associate of the IFS and a Professor in the Department of Economics, KU Leuven.
Bram De Rock
Bram is a Research Associate of the IFS, a Professor of Economics at ULB and a Professor of Mathematics and Statistics at KU Leuven.
Frederic Vermeulen
Frederic is a Research Associate of the IFS, a Professor of Economics at the University of Leuven and a Research Fellow at the CEPR.
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