Between the farm and the dinner table: The impact of farm share on body mass index in the United States of America

When Americans buy food at the grocery store, only a fraction of the price they pay goes to the farmers who grew the original ingredients. This is called the farm share. The rest of the food dollar pays for additional services, such as food transportation, distribution, processing, and advertising. Over the past half-century, the overall farm share of the U.S. food supply has fallen. At the same, obesity rates have been rising steadily. This paper explores the relationship between these two concurrent phenomena, hypothesizing an inverse relationship between Americans' body mass index and the overall farm share of their diet. Using U.S. Department of Agriculture farm share calculations for a variety of food types, combined with data on people's eating habits, a variable is constructed to represent the total farm share of each person's diet. An ordinary least squares (OLS) regression model is used to investigate a link between this farm share variable and individuals' body mass index, controlling for demographics and physical activity. The results support the hypothesis, finding an inverse relationship between farm share and body mass index. These results suggest that the obesity epidemic could be mitigated by policies that support the consumption of foods with high farm shares.