Recently the only non-profit academic society dedicated to promoting the science and application of evidence-based sports nutrition and supplementation, The International Society of Sports Nutrition (ISSN), released an updated position on nutrient timing for endurance athletes. Here are some of the key takeaways:
Carbohydrate Timing
Pre-Exercise
For complete restoration of carbohydrate stores follow a high-carbohydrate diet of 8 to 12 grams of carbohydrate per kilogram (3.6 to 5.4 grams per pound). This method of fueling is ideal the day before a long race (1/2 marathon to Ultra) or long training run and is commonly know has “carb loading.”
Post-Exercise
For fast replenishment (less then 4 hours) of carbohydrate stores following a hard workout or race it’s best to seek 1.2 grams per kg per hour (0.5 grams per pound per hour) of fast acting, high glycemic index (greater then 70) carb sources with a combination of caffeine (3 to 8mg per kg) and protein (0.2–0.4 g/kg/h)
During Exercise
For runs lasting longer then 60 minutes ingest 30 to 60 grams of carbohydrate-electrolyte solution per hour to maintain adequate carbohydrate stores. It’s important to note there is benefit in training without ingesting carbohydrates. Carbohydrate intake is ideal for when high performance is the goal.
During Resistance Training
Consuming carbohydrate solely or in combination with protein during resistance exercise increases muscle glycogen stores, ameliorates muscle damage, and facilitates greater acute and chronic training adaptations.
Protein Timing
Protein intake is best spaced out in 3 to 4 hour increments of 20 to 40 grams for a daily total of 0.25 to 0.40 grams per kilogram (0.11 to 0.18 grams per pound).
Post-exercise ingestion (immediately to 2-h post) of high-quality protein sources stimulates robust increases in muscle protein syntheses (MPS).
Consuming casein protein (~ 30–40 g) prior to sleep can acutely increase MPS and metabolic rate throughout the night without influencing lipolysis.
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