Although epigenetic aberrations frequently occur in aging and cancer and form a core component of these conditions, perhaps the most useful aspect of epigenetic processes is that they are readily reversible. Unlike genetic effects that also play a role in cancer and aging, epigenetic aberrations can be relatively easily corrected. One of the most widespread approaches to the epigenetic alterations in cancer and aging is dietary control. This can be achieved not only through the quality of the diet, but also through the quantity of calories that are consumed. Many phytochemicals such as sulforaphane from cruciferous vegetables and green tea have anticancer epigenetic effects and are also efficacious for preventing or treating the epigenetic aberrations of other age-associated diseases besides cancer. Likewise, the quantity of calories that are consumed has proven to be advantageous in preventing cancer and extending the lifespan through control of epigenetic mediators. The purpose of this chapter is to review some of the most recent advances in the epigenetics of cancer and aging and to provide insights into advances being made with respect to dietary intervention into these biological processes that have vast health implications and high translational potential.