Trimming Obesity

The overarching objective of our research on improving the quality of nutrition is to carry out quantitative research that can inform public policy as to the more effective means to combat obesity.  At the center of the current debate is whether policy makers should focus on strategies that attack the supply side of the problem (sugar taxes, advertising bans, etc.) or on strategies to shift consumer habits (e.g. educational programs that increase the public awareness of the problem). Our long term goal is to provide a comprehensive answer to this controversy by uncovering what forces are likely to play a more important role in the decay of consumption of nutritional quality in the U.S. So far, we have made industry-specific contributions towards this goal (soda and ready-to-eat cereal), and are working on an ambitious research agenda that can encompass all industries.

We have studied extensively whether quantitative analysis supports the notion that soda taxes can successfully reduce sugar consumption (and therefore obesity incidence).  As opposed to earlier literature, our approach has focused on including an important aspect of the market: the possibility that consumers, when faced with low prices, may store the product for future consumption. Our main finding is that stockpiling behavior prevents soda taxes from being as effective as they would otherwise be in reducing consumption. The reason is simple: people take advantage of periods when soda is on sale and purchase then rather than when soda is not on sale (when the value added tax has the greatest effect). As a consequence, our research shows that this solution to the problem is much less effective than previously thought, primarily because consumers take the future into account when making their purchase decisions.

Another industry we have scrutinized is ready-to-eat cereal. We have asked the question of how the nutritional quality of this staple food category has evolved over time in the U.S. and whether such quality differs across cities. By building a dataset on the sales, prices and nutrition information of dozens of cereal brands in several cities in the U.S. we have constructed and studied indices of the overall quality of this food category. Besides being able to paint a picture of how nutritional quality has evolved over time, our analysis also allows us to ask the question of why two cities may exhibit important differences in the observed index of nutritional quality. The answer to this latter question is important because we can tease out whether the nutrition quality in one region is worse because consumers simply gravitate more to less healthy brands or, alternatively, because healthier alternatives are not present there (or are more expensive).  Surprisingly, we find that nutritional quality has been improving since the start of this century, people still eat less healthy than in 1988.

Another surprising result is that the reasons for observing cities with less healthy eating appear to be driven by consumer preferences (healthier alternatives are present pretty much everywhere and have not become more expensive over time).  We also find that while three decades ago people in different cities were relatively similar in the quality of nutritional intake, over time the quality of consumption has diffused significantly.