Consumer knowledge, food label use and grain consumption in the US

Abstract

Responding to mounting evidence of the association between whole-grain consumption and a reduced risk of heart problems and other diseases, as well as an increased probability of body weight maintenance, the US Government has strongly encouraged its citizens to increase consumption of whole grains. However, compared against the 2005 Federal dietary recommendations, in 1994–1996 only 6% of Americans met the current recommended whole-grain consumption. To narrow this huge gap between actual and recommended consumption of whole grains, considerable changes in consumer behaviour will be needed. A demand system with two censored consumption equations and endogenous food label use and nutrition knowledge variables is estimated to investigate the factors that affect the consumption of whole and refined grains. Food label use and nutrition knowledge are found to play important roles in the consumption of refined- and whole-grain products, as are sociodemographic variables. The results can be used to help develop effective nutrition education messages and targeting strategies to promote consumption of whole grains in Americans’ diets.

Acknowledgements

Senior authorship is shared. The authors benefited from insightful discussions with Lung-Fei Lee. Thanks are also due to Kristin Marcoe and Andrea Carlson for assistance with data preparation, and to Jean Buzby, Lisa Mancino, Joanne Guthrie and an anonymous referee for helpful comments and suggestions. Regular disclaimer applies. Research for this article was supported by USDA-ERS Cooperative Agreement 43-3AEM-4-80052. The views in this article are those of the authors and do not necessarily reflect the views or policies of the US Department of Agriculture.

Notes

¹ We present the bivariate censored system with dual endogenous binary regressors for ease of exposition. A larger system with a different number of endogenous variables can be estimated with slight changes in the likelihood function. Estimation of the censored system is slightly easier with continuous (vs. discrete) endogenous variable(s) which do not introduce additional integrals as the binary variables do (Yen et al ., 2005).

² As noted above zero observations of refined grains occur in a very small proportion of the sample, but a two-zero regime is nevertheless reflective of the sample.

³ Given the distribution e* ∼ (0, Ω), partition Ω at the third row with submatrices Ω₁₁, Ω₁₂, Ω₂₁ and Ω₂₂ such that Ω₁₁ is 3 × 3 and Ω₂₂ is 1 × 1. Then using properties of the multivariate normal distribution (Kotz et al ., 2000), we have u ₄ ∼ (0, Ω₂₂) and

⁴ The effects of explanatory variables on the probabilities of food label use and importance of grains can be derived from Pr(y_i  = 1) = Φ(z′α_i ) for i = 1, 2. These marginal effects are presented in the appendix.

⁵ The refined-grain equation is hardly censored so the effects of explanatory variables on the unconditional means are reflected by the parameter estimates of the equation.