The amount of nutrients required by an individual is determined by a number of physiological processes, including absorption, metabolism, stability, and bio-activation. These processes determine nutrient needs and provide variations in requirements in the population. All have modifiers and sensitizers, such as sex, genetics, pregnancy, age, pharmaceuticals, toxins, food matrix, and epigenetics. Disease can also be a major modifier of these processes. In April 2018, the National Academies of Science, Engineering and Medicine convened a workshop in order to explore the evidence for special nutritional requirements in disease states and the medical conditions that cannot be met with a normal diet. Participants explored the impact a disease state can have on nutrient metabolism and nutritional status, and attempted to close informational gaps. This publication summarizes the presentations and discussions from the workshop.