Why This File Exists

The endurance nutrition space is loud, opinionated, and full of advice that contradicts itself month to month. This file exists for one reason: every recommendation in the ANC Race & Training Fueling Library can be traced to peer-reviewed research, an IOC or ACSM consensus statement, or a well-replicated clinical or field study.

How to Read This File

Each topic chapter is structured the same way: The Claim, The Evidence, The Caveats, and The Application — pointing back to the specific playbooks where each finding is applied.

Carb Loading & Supercompensation

The Claim: A 36–48 hour high-carb intervention (9–12 g/kg/day) combined with reduced training volume produces glycogen supercompensation in trained athletes, improving performance in events >90 minutes. The depletion phase of the classical protocol is unnecessary.

Applied in

• The Carb Loading Playbook
• The Race Morning Playbook

Race-Day Carbohydrate Intake

The Claim: In-race carbohydrate intake of 60–120 g/hr improves performance in endurance events >90 minutes. Recent evidence supports the upper end (90–120 g/hr) in gut-trained athletes for events >3 hours.

Applied in

• The In-Race Fueling Deep Dive
• The Training Fuel Handbook

Dual Transporters & the 60 g/hr Wall

The Claim: Single-transporter carbohydrate products saturate at approximately 60 g/hr. Co-ingestion of fructose allows absorption up to 90–120 g/hr.

Applied in

• The In-Race Fueling Deep Dive
• The Training Fuel Handbook

Gut Physiology & Run-vs-Bike

The Claim: Running mechanically and physiologically reduces gut tolerance for carbohydrate compared to cycling. Run g/hr targets should be set at approximately 78–85% of bike g/hr targets.

Applied in

• The In-Race Fueling Deep Dive

Hydration & Hyponatremia

The Claim: In-race fluid intake of approximately 75% of sweat-rate losses, paired with sodium intake calibrated to individual sweat sodium loss, optimizes performance and minimizes hyponatremia risk.

Applied in

• The In-Race Fueling Deep Dive
• The Race Conditions Playbook

Caffeine

The Claim: Caffeine at 1–3 mg/kg body weight improves endurance performance by 3–6% through reduced perceived exertion and increased central drive.

Applied in

• The In-Race Fueling Deep Dive
• The Race Morning Playbook

Carb Mouth Rinse

The Claim: Swishing a 6% carbohydrate solution for 5–10 seconds without swallowing improves performance by 2–3% in events under 60 minutes via central nervous system mechanisms.

Recovery & the Post-Exercise Window

The Claim: Consuming 1.0–1.2 g/kg carbohydrate plus 20–40 g protein within 30 minutes of finishing a hard or long session maximizes glycogen resynthesis and muscle protein synthesis.

Applied in

• The Training Fuel Handbook

Female Athletes, Iron & RED-S

The Claim: Female endurance athletes have distinct physiological considerations: cycle-phase variations in thermoregulation and substrate use, elevated iron deficiency risk, and significant RED-S prevalence.

Applied in

• The Training Fuel Handbook
• The Race Conditions Playbook

Gut Training as a Skill

The Claim: The gut is a trainable organ. Progressive exposure to high carbohydrate intake during exercise — over 4–12 weeks — increases tolerance and absorption capacity.

Applied in

• The Training Fuel Handbook
• The In-Race Fueling Deep Dive

How This Evidence Shows Up in the Playbooks

Every playbook in the library draws on the citations in this file.

Science You Can Race On

The library you've just read is built on this foundation. The plan you build for race day deserves the same rigor.