Personalized nutrition holds tremendous potential to improve human health. Despite exponential growth, the field has yet to be clearly delineated and a consensus definition of the term "personalized nutrition" (PN) has not been developed. Defining and delineating the field will foster standardization and scalability in research, data, training, products, services, and clinical practice; and assist in driving favorable policy. Building on the seminal work of pioneering thought leaders across disciplines, we propose that personalized nutrition be defined as: a field that leverages human individuality to drive nutrition strategies that prevent, manage, and treat disease and optimize health, and be delineated by three synergistic elements: PN science and data, PN professional education and training, and PN guidance and therapeutics. Herein we describe the application of PN in these areas and discuss challenges and solutions that the field faces as it evolves. This and future work will contribute to the continued refinement and growth of the field of PN.Teaching points PN approaches can be most effective when there is consensus regarding its definition and applications. PN can be delineated into three main areas of application: PN science and data, PN education and training, PN guidance and therapeutics. PN science and data foster understanding about the impact of genetic, phenotypic, biochemical and nutritional inputs on an individual's health. PN education and training equip a variety of healthcare professionals to apply PN strategies in many healthcare settings. PN professionals have greater ability to tailor interventions via PN guidance and therapeutics. Favorable policy allows PN to be more fully integrated into the healthcare system.