Serious inconsistencies and scientific gaps plague current dietary recommendations, especially when it comes to cancer. Moreover, these recommendations crash head on with many traditional, ethnic, and cultural practices around the world. Until we openly address what led to these recommendations, the overwhelming impact of philosophical and religious beliefs over science, and the fatal inconsistencies that lie within, we will be unable to have a candid conversation about what we should eat to fight cancer. Did Leonardo, a poor shepherd from southern Italy, know this all along? Leonardo's Legacy is a first attempt to start this conversation.