Clinical Sports Nutrition

Nutrition Basics for Athletes

Clinical sports nutrition builds on the fundamental principles of dieteticsmacronutrient balance, micronutrient adequacy, and individualized energy intakewhile tailoring them to the physiological demands of training and competition.

Macronutrients

• Carbohydrates are the primary fuel for highintensity work. Athletes typically consume 510gkgday, adjusting for sport type and training volume.
• Proteins support muscle repair, immune function, and hormone synthesis. Recommendations range from 1.22.0gkgday, with higher intakes for strengthbased sports.
• Fats provide essential fatty acids and serve as a fuel source during prolonged, moderateintensity activity. Aim for 2035% of total calories, emphasizing mono and polyunsaturated fats.

Micronutrients

Vitamins and minerals become especially critical under heavy training loads. Iron, calcium, vitamin D, and the Bvitamin complex are frequently monitored because deficiencies can impair performance, bone health, and oxygen transport.

Energy Systems & Fuel Timing

Understanding how the body produces ATP allows clinicians to prescribe precise nutrient timing strategies.

Phosphagen (ATPCP) System

Lasting ~10seconds, this system relies on stored ATP and creatine phosphate. Adequate creatine intake (35g/day) can enhance phosphagen capacity for sprinters and weightlifters.

Glycolytic (Anaerobic) System

Dominates efforts lasting 30seconds to 2minutes. Rapid carbohydrate availability is essential; a preexercise snack containing 2030g of highglycemic carbs 30minutes before activity can improve output.

Oxidative (Aerobic) System

Supports endurance events >2minutes. Carbohydrate loading (10gkgday) 4872hours before a race maximizes muscle glycogen stores.

Hydration Strategies

Dehydration as little as 2% body mass loss can impair cognitive function and aerobic performance. Clinical assessment includes urine specific gravity, plasma osmolality, and sweat rate testing.

PreExercise Hydration

Consume 57mlkg of water or a carbohydrateelectrolyte solution 23hours before activity. Adjust volume based on urine color (light straw is ideal).

During Exercise

Replace fluid at a rate matching sweat loss (0.51Lhour). Add 3060mmolL sodium to prevent hyponatremia, especially in events >1hour.

PostExercise Rehydration

Consume 150% of the fluid lost within 2hours. A practical formula: Weight change (kg)1500ml plus the volume of any urine produced.

Recovery Nutrition

Recovery is a critical window for adaptation. The first 3060minutes postexercise is often called the anabolic window.

ProteinCarbohydrate Combination

Evidence supports 0.30.4gkg of highquality protein with 0.81.2gkg of carbohydrate within 30minutes after training. This stimulates muscle protein synthesis and restores glycogen.

AntiInflammatory Nutrients

Omega3 fatty acids (EPA/DHA 12g/day), curcumin (500mg), and tart cherry juice (30ml) have shown modest reductions in postexercise inflammation and soreness.

Sleep and Nutrition

Melatoninrich foods (e.g., tart cherries, walnuts) and a modest protein dose (~20g) before bedtime can support muscle repair and improve sleep quality.

Special Populations

Adolescent Athletes

Growth, hormonal changes, and training load create unique nutritional needs. Emphasize adequate calories, calcium (1300mg/day), and iron (11mg for females, 15mg for males). Periodized nutrition aligns with training blocks.

Female Athletes

Address the Female Athlete Triad (energy deficiency, menstrual dysfunction, low bone mineral density). Energy availability should stay above 45kcalkgFFMday. Vitamin D (2000IU/day) and iron status are routinely monitored.

Veteran/ Masters Athletes

With advancing age, protein anabolic resistance increases. Aim for 1.52.0gkgday, spread across 34 meals. Antioxidant-rich foods help mitigate oxidative stress from chronic training.

Practical Tools for Clinicians

• Nutrition Assessment: 24hour recall, food frequency questionnaire, and diet history combined with body composition analysis.
• Energy Availability Calculator: EA = (EIEE)/FFM where EI = energy intake, EE = exercise energy expenditure, FFM = fatfree mass.
• Food Timing Apps: Programs like MyFitnessPal, Chronometer, or sportspecific platforms (e.g., InsideTracker) help athletes log intake and sync with training logs.
• Lab Testing: Regular panels for iron, ferritin, vitamin D, calcium, and thyroid function ensure micronutrient adequacy.
• Education Materials: Handouts on carbohydrate loading, hydration strategies, and postexercise recovery recipes support adherence.

Sample Daily Meal Plan (2500kcal, 55% CHO, 20% PRO, 25% FAT)

Breakfast (07:00)- Oatmeal (80g) topped with banana, blueberries, and 1tbsp almond butter- Greek yogurt (150g) with honey- 250ml orange juiceMidMorning Snack (10:00)- Wholegrain toast with avocado and smoked salmon- WaterPreWorkout (12:30)- Apple slices with 15g whey protein mixed in waterPostWorkout (14:30)- Recovery shake: 30g whey, 60g maltodextrin, 5g creatine, 500ml water- Chocolate milk (250ml)Lunch (16:00)- Quinoa salad with grilled chicken, mixed greens, chickpeas, feta, and oliveoil vinaigrette- Sweet potato (150g)Afternoon Snack (18:30)- Trail mix (nuts, seeds, dried fruit) 30g- Electrolyte waterDinner (20:30)- Baked salmon (150g) with lemondill sauce- Brown rice (120g) and steamed broccoli- Side salad with olive oilEvening Snack (22:00)- Cottage cheese (200g) with pineapple chunks- Chamomile tea