The Role of Macronutrients in Athletic Performance
Reviewed by Andrea Dacey, RDN, CSSD | Updated August 15, 2026 What Carbs, Protein, and Fat Actually Do for Athletes Macronutrient advice tends to arrive as a ratio — 40/30/30, …
Look for a Registered Dietitian (RD/RDN) with a Board Certified Specialist in Sports Dietetics (CSSD) credential — this ensures your coach has both clinical nutrition training and sport-specific expertise. Ask about their experience working with your sport and competition level, whether they build individualized plans versus generic templates, and how they coordinate with your coach or medical team.
Ask about their credentials (RDN, CSSD), experience with athletes at your level, and how they structure the assessment and coaching process. Find out whether plans are personalized based on testing or built from general guidelines, how often you'll meet, and how they measure progress.
Personalization starts with data — resting metabolic rate, training volume, body composition, and event demands — rather than one-size-fits-all calorie targets. Plans are reassessed as training phases and goals shift.
Yes — proper fueling directly affects glycogen availability, hydration status, and recovery capacity, all of which influence endurance output. Underfueling is one of the most overlooked limiters of performance gains.
Even mild dehydration (as little as 2% of body weight) can measurably reduce endurance capacity, strength output, and cognitive focus during competition. A sports dietitian can help build a personalized hydration and electrolyte strategy.
High training loads can temporarily suppress immune function, making adequate protein, vitamin D, zinc, and overall energy availability especially important. Underfueling is a common driver of frequent illness and slow recovery.
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