On the gene-nutrient analyses of Cahill et al.

which are more prevalent in low-income communities (5–7). The reasons underlying the suboptimal intake of fruits and vegetables in the United States are likely to be varied and complex and require much further investigation. I agree that food price influences food choice and that energy cost is inversely related to energy density. However, it does not necessarily follow that energy cost is the specific food price measure that determines purchasing decisions, nor that price and/or energy content are the only considerations. Future research should not rely on the use of energy cost until it is validated as an appropriate measure of food price.