Research
Macro partitioning
Carbohydrate loading (10–12 g/kg/day for 36–48 hours) improves performance by 2–3% and delays fatigue in endurance events lasting longer than 90 minutes.
If you are competing in an event lasting over 90 minutes (like a marathon or long triathlon), eat 10–12 grams of carbohydrates for every kilogram of your body weight each day for the 2 days before the race. This maximizes your muscle fuel stores and helps you delay fatigue.
GoodSupportsHIGH confidence
Benefits include delayed onset of fatigue (approximately 20%) and improvement in performance of 2%–3%. Current recommendations suggest that for sustained or intermittent exercise longer than 90 minutes, athletes should consume 10–12 g of carbohydrate per kg of body mass (BM) per day in the 36–48 hours prior to exercise.
Why this rating
Supported by multiple studies and consensus recommendations, though the paper notes it is not beneficial for events under 90 minutes.
Source
Role of nutrition in performance enhancement and postexercise recovery
Kathryn L. Beck et al. · Open Access Journal of Sports Medicine · 2015
DOI 10.2147/oajsm.s33605
narrative_reviewCited 216×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
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- Dietary supplements carry a significant risk of inadvertent doping violations due to contamination, despite widespread use among athletes.Good
- Training with low carbohydrate availability ('train-low') enhances metabolic adaptations (e.g., mitochondrial enzyme activity) but does not improve performance compared to training with high carbohydrate availability.Moderate
Related findings · Macro partitioning
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- Resistance exercise training combined with sufficient dietary protein intake acts synergistically to maximize skeletal muscle hypertrophy, with protein intake saturating around 1.6 g/kg/day for general populations and potentially requiring 2.0-2.2 g/kg/day for resistance-trained individuals.Strong
- Trans fats should be completely eliminated from the diet, as they increase LDL cholesterol, decrease HDL cholesterol, and are directly associated with increased coronary risk.Strong
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