adaptationathletesavailabilitybehindbeyondburkecarbohydratecollagencyclingcyclistcyclistsdanadietsdigestiondistresseatingeliteelliottenduranceexerciseexogenousfemaleftpfuturegroundworkguthealthimplicationsinsideironjamesjamieketogenicketoneskirstylewislislouisemortonmscmusclenutritionnutritionistspatrickpeelingperformancepeterphdpropughresearchroadrolesalescienceseriessportsstephenstomachstrategiessupplementationteixeirathermaltrainingwilson