Responding to mounting evidence of the association between whole-grain consumption and a reduced risk of heart problems and other diseases as well as body weight maintenance, the U.S. Government has strongly encouraged its citizens to increase consumption of whole grains. However, compared against the 2005 Federal dietary recommendations, in 1994-96 only 6 percent of Americans met the current recommended whole-grain consumption. To narrow this huge gap between actual and recommended consumption of whole grains, an effective nutrition education campaign is needed. A demand system with two censored consumption equations and two endogenous knowledge and attitude variables is estimated to investigate the factors that affect the consumption of whole and refined grains. The results can be used to help develop an effective education campaign in promoting consumption of whole grains in Americans' diets.