There are biomarkers for many aspects of biology. In this introductory lecture, Kaput illustrated how genes can contribute to the development of common diseases, such as type 2 diabetes. Although randomized controlled trials remain the gold standard of evidence-based medicine, it should be acknowledged that data from clinical trials are but averages of the sample populations’ responses to particular interventions. Genetically, each individual is unique. As individuals are genetically and biochemically distinct, Kaput argued that humans should not be randomized into groups. Both dietary and lifestyle factors contribute to the heterogeneity observed in clinical trials. Similarly, a single phenotype can result from multiple independent pathways. Developing individual risk or benefit factors in light of the genetic diversity of human populations, the complexity of foods, culture and lifestyle, as well as the variety of metabolic processes leading to health or disease, are all significant challenges for personalizing dietary advice.