The Human Genome and HapMap projects have provided the tools and information that will aid in understanding how nutrients alter the expression of an individual's genetic information and why individuals differ in metabolism of foods at the molecular level. The study of how genes and gene products interact with dietary chemicals to alter phenotype and, conversely, how genes and their products metabolize nutrients is called nutritional genomics or "nutrigenomics." This new field has received considerable attention in the last 6 years, most of which has been on the promise rather than on scientific results from nutrigenomic experiments. Funding for nutrigenomics research focused primarily on individual laboratory projects in the 1990s and early 2000s. The novelty of combining nutrition and genetics limited that funding to a relatively small number of laboratories. Only in the past 3 years have centers been funded to foster collaborations and conduct large-scale projects that are studying nutrient-gene interactions. The increase in interest and funding is beginning to generate the critical mass to realize the promise of nutritional genomics.