Trends in Americans' food-related time use: 1975-2006.

OBJECTIVE: To describe how the time spent in food-related activities by Americans has changed over the past 30 years.
DESIGN: Data from four national time diary surveys, spanning 1975-2006, are used to construct estimates of trends in American adults' time spent in food-related activities. Multivariate Tobits assess how food-related activities have changed over time controlling for sociodemographic and economic covariates.
RESULTS: Both bivariate and multivariate estimates reveal that between 1975 and 2006, American women's time spent in food preparation declined substantially, whereas the time spent in these activities by American men changed very little. On the contrary, grocery shopping time increased modestly for both men and women. The primary eating time (i.e. time when eating/drinking was the respondent's main focus) declined for both men and women over this historical period, and the composition of this time changed with less primary eating time being done alone. Concurrently, secondary eating time (i.e. time when something else had the respondent's primary attention, but eating/drinking simultaneously occurred) rose precipitously for both women and men between 1975 and 1998.
CONCLUSIONS: The total time spent in eating (i.e. primary plus secondary eating time) has increased over the past 30 years, and the composition of this time has shifted from situations in which energy intake can be easily monitored to those in which energy intake may be more difficult to gauge. Less time is also being spent in food preparation and clean-up activities. Future research should explore possible links between these trends and Americans' growing obesity risk.