The provision or restriction of select nutrients in an athlete's diet can elicit a variety of changes in fuel utilization, training adaptation, and performance outcomes. On this episode we discuss the impact of both acute and chronic carbohydrate restriction on iron metabolism, comparing models of periodized carbohydrate availability and ketogenic low carbohydrate high fat diets. We also touch base on the link between low energy availability , poor iron status and altered hepcidin activity in endurante athletes.