Nutrition for Athletes

The Performance Nutrition Advantage

For athletes, nutrition is not merely about health; it is a direct performance variable. The difference between optimal and suboptimal fuelling can determine race outcomes, recovery speed, and career longevity. Modern sports nutrition has moved far beyond simple calorie counting into precise, periodised, and increasingly personalised approaches.

A 2018 consensus statement from the International Olympic Committee confirmed that strategic nutrition planning can improve performance by 1-3%, a margin that separates medal positions in elite competition.

Carbohydrate Periodisation

The concept of "fuelling for the work required" has replaced the outdated approach of eating high-carb at all times. Modern carbohydrate periodisation strategically varies carb intake based on training demands.

• High-carb days (8-12 g/kg) are reserved for intense training sessions and competition to maximise glycogen stores and sustain high-intensity output
• Low-carb or "train low" days (3-5 g/kg) are used during low-intensity or recovery sessions to enhance mitochondrial biogenesis and fat oxidation capacity
• A 2016 study in the Journal of Applied Physiology demonstrated that periodised carb intake improved endurance performance by 3-5% compared to a consistently high-carb approach
• "Sleep low, train low" protocols (restricting carbs after evening training to train fasted the next morning) increase expression of fat oxidation enzymes by up to 25%
• During endurance events exceeding 2.5 hours, consuming 60-90 g of carbohydrate per hour using multiple transportable carbohydrates (glucose + fructose in a 2:1 ratio) maximises absorption and performance

Protein Timing & the Leucine Threshold

For athletes, protein quantity matters, but timing and quality matter just as much.

• The leucine threshold, the minimum leucine content needed to maximally stimulate muscle protein synthesis, is approximately 2.5-3 g per serving. This corresponds to roughly 25-40 g of high-quality protein
• Distributing protein across 4-5 meals spaced 3-4 hours apart produces superior muscle protein synthesis compared to the same total protein in fewer, larger meals
• Post-exercise protein intake within the first 0-2 hours maximises the elevated muscle protein synthesis response, though the "anabolic window" is wider than previously believed
• Athletes require 1.6-2.2 g/kg/day of protein during training phases, with some evidence supporting up to 2.7 g/kg during caloric restriction to preserve lean mass
• Pre-sleep protein (30-40 g of casein or a casein-rich whole food) has been shown to increase overnight muscle protein synthesis by 22% and improve next-morning recovery metrics

Recovery Nutrition

What you eat in the hours after training determines how effectively you adapt to the training stimulus and how quickly you can perform again.

• The glycogen resynthesis rate is highest in the first 30-60 minutes post-exercise (up to 1.5x normal rate). Consuming 1-1.2 g/kg of carbohydrate during this window maximises glycogen replenishment
• Combining carbohydrate with protein in a 3:1 or 4:1 ratio post-exercise enhances glycogen resynthesis by an additional 40% compared to carbohydrate alone
• Tart cherry juice (equivalent to 50-60 cherries) has been shown to reduce muscle soreness by 13% and accelerate strength recovery by 12%, attributed to its anthocyanin content
• Omega-3 supplementation (2-4 g/day EPA+DHA) reduces exercise-induced inflammation and muscle soreness, with measurable effects appearing after 2-4 weeks of consistent use
• Creatine monohydrate (3-5 g/day) remains the most evidence-supported ergogenic supplement, improving high-intensity exercise performance by 10-20% and supporting recovery between bouts

Metabolic Flexibility & Keto-Adaptation

Metabolic flexibility, the ability to efficiently switch between carbohydrate and fat as fuel sources, is increasingly recognised as a marker of athletic fitness and metabolic health.

• Fat-adapted athletes can oxidise fat at rates up to 1.5-1.8 g/min, compared to 0.5 g/min in carb-dependent athletes, providing a virtually unlimited energy source for ultra-endurance events
• The FASTER study found that elite fat-adapted ultra-runners burned 2.3x more fat at peak oxidation rates while maintaining similar glycogen usage to high-carb runners
• Keto-adaptation typically requires 4-12 weeks of strict carbohydrate restriction (less than 50 g/day) and is accompanied by a temporary performance decline during adaptation
• Fat adaptation appears most beneficial for ultra-endurance events (races exceeding 3-4 hours) and least beneficial for high-intensity, glycolytic sports (sprinting, weightlifting, team sports)
• Many elite coaches now employ a hybrid approach: building a fat-oxidation base during off-season while strategically reintroducing carbohydrates for high-intensity competition periods

Data-Driven Nutrition

The era of guesswork in sports nutrition is ending. Real-time metabolic data allows athletes to personalise fuelling strategies with unprecedented precision.

• Continuous glucose monitors (CGMs) reveal individual glycaemic responses to pre-race meals, allowing athletes to identify which foods provide stable energy versus those causing reactive hypoglycaemia
• Ketone monitors help fat-adapted athletes verify they are maintaining nutritional ketosis (0.5-3.0 mmol/L) and can identify when carbohydrate reintroduction knocks them out of the fat-burning zone
• Blood lactate testing during training helps determine the crossover point where fat oxidation gives way to carbohydrate dependence, allowing targeted fuelling at specific intensities
• Sweat sodium testing enables personalised hydration plans: individual sweat sodium concentration varies from 200-1,800 mg/L, making one-size-fits-all electrolyte advice unreliable
• Elite athletes increasingly use CGMs and ketone monitors to fine-tune fuelling strategies. Explore performance health devices at Healthspan.mu

Honest Risks & Considerations

A balanced view of the evidence for athletic nutrition strategies:

• Relative Energy Deficiency in Sport (RED-S) is a serious condition caused by insufficient caloric intake relative to energy expenditure. It affects bone health, hormonal function, immunity, and cardiovascular health in both male and female athletes
• Extreme dietary restriction for weight-class sports or aesthetic sports carries significant health risks including eating disorders, menstrual dysfunction, and stress fractures
• Supplement contamination is a documented risk. A 2020 analysis found that 12-25% of supplements contained substances not listed on the label. Athletes subject to anti-doping rules should only use products certified by NSF Certified for Sport or Informed Sport
• Individual variation is enormous. What works for one athlete may not work for another. Evidence-based guidelines are starting points, not prescriptions. Systematic self-experimentation with careful tracking is essential
• The gut is trainable. Athletes should practise their race-day nutrition strategy during training. Gastrointestinal distress during competition is most often caused by untested fuelling rather than inherent intolerance