Grazing, Goods, and Girth

When time becomes more valuable (as proxied by the hourly wage), then people substitute grazing for eating, in essence multi-tasking this essential activity.

In Grazing, Goods, and Girth: Determinants and Effects (NBER Working Paper No. 15277) NBER Research Associate Daniel Hamermesh uses a newly-created nationally representative dataset (the 2006-7 American Time Use Survey and its Eating and Health Module) to study eating patterns and how they relate to wage rates. He distinguishes between primary eating/drinking (which he refers to as "eating") and secondary eating/drinking while engaged in another primary activity (he refers to this as "grazing"). One example of grazing is munching on a muffin while working at the computer -- the primary activity is market work, and grazing occurs at the same time.

Hamermesh finds that over half of adult Americans report grazing on a typical day, and that grazing time almost equals primary eating/drinking time. Economic models would predict that higher wage rates (that is, the price of time) will lead to the substitution of grazing for primary eating/drinking, especially by raising the number of grazing intervals relative to meals. The data used in this study confirm those predictions.

Hamermesh suggests that the most interesting finding here relates the frequency of eating to weight and health outcomes. Those who eat more meals, conditional on total time spent eating, weigh less and report better health and lower Body Mass Index (BMI) than their demographically-identical counterparts. Further, the distribution of time spent eating is an economic outcome: when time becomes more valuable (as proxied by the hourly wage), then people substitute grazing for eating, in essence multi-tasking this essential activity.

The general economic question throughout this paper is how the value of time, and time use, affect the process of eating and its impact on health and BMI. Hamermesh provides us with a glimpse into how economic considerations partly determine the timing and amount of eating, and how those choices about eating affect our health and weight.

-- Lester Picker