Distributional analyses on diet quality in the United States

Abstract

This dissertation takes a distributional approach to examining dietary quality in the United States. Diet quality is a direct input to health, is often used as a proxy for well-being, and is an outcome variable for a wide variety of economic interventions. This makes diet quality a particularly important, yet understudied, outcome for program evaluation and describing food bundles that individuals choose. The first chapter describes the evolution of adult dietary quality in the U.S. over the last two decades. Contrary to popular wisdom, there have been statistically significant improvements at all levels of diet quality. For the population as a whole, we find significant improvements across all levels of diet quality. Further, we find improvements for both low-income and higher-income individuals alike. Counterfactual distributions of dietary quality are constructed to investigate the extent to which observed improvements can be attributed to changes in the nutritional content of foods and to changes in population characteristics. We find that 63% of the improvement for all adults can be attributed to changes in food formulation and demographics. Changes in food formulation account for a substantially larger percentage of the dietary improvement within the lower-income population (19.6%) as compared to their higher-income counterpart (6.4%). The sheer myriad of overlapping policies and public awareness initiatives during this time period make it difficult to pin down the exact causes behind such improvements. This chapter motivates two program evaluation studies in the two chapters that follow.The second chapter estimates distributional effects of food consumed at school and away from home on child dietary quality. Using a fixed-effects quantile estimator, two non-consecutive days of food intake are used to identify the effect of eating away from home and at school. I find considerable heterogeneity in the estimated impacts. The study finds that food away from home, as compared to home-prepared food, has a negative impact on the distribution of dietary quality except at low quantiles. Main results suggest that school food has both positive and negative impacts across the distribution of dietary quality. I find positive impacts on dietary quality at low quantiles of the outcome distribution, whereas food from school has a negative impact at the upper end of the distribution of diet quality. While food consumed under the National School Lunch and Breakfast Programs may not benefit every child, especially the average child, it does improve the diets of many children who otherwise would have poorer dietary quality. The implication is that U.S. schools are fertile grounds to improve nutrition skill formation, especially for the most nutritionally disadvantaged. This final chapter estimates the effect of replacing food assistance benefits, which typically come in the form of a food voucher, for an equal value of cash on the quantity and quality of food consumed in a household. We utilize an experiment in which a portion of beneficiaries were chosen at random to receive their benefits in the form of cash. We take a distributional approach because we believe it is important to analyze low-consuming households separate from high-consuming households. We find some evidence that a cash system would increase kilocalorie consumption in the portion of the distribution below recommended levels of consumption and decrease consumption in the portion of the distribution well above any reasonable threshold. This finding implies that a cash transfer system may both alleviate food insecurity and decrease overconsumption. The cash system appears to have a positive impact on the distribution of dietary quality in quantiles above 40. Virtually all of the improvement in quality comes from a decrease in consumption of less-healthy foods by the cash receiving group. Overall, these findings imply that beneficiaries are no worse off under a cash transfer system and in fact, may be better off.