Fuel Your Endurance Journey

Consume 1–4g of carbs per kg of body weight 1–4 hours before exercise, depending on your gut comfort and session intensity. A 70kg athlete might eat 70–280g carbs, ranging from a full meal (70–140g, 3–4 hours before) to a light snack (35–70g, 1–2 hours before). Include moderate protein and minimal fiber/fat to avoid GI distress. Hydrate with 400–600ml fluid 2–3 hours prior, then another 200–300ml 20 minutes before start.

Within 30–120 minutes, aim for a carb-to-protein ratio of 3:1 or 4:1 with a total carb intake of 1–1.2g per kg body weight. For a 70kg athlete after a 2-hour session, this means 70–84g carbs and 18–28g protein. Examples: 500ml chocolate milk plus a banana, 100g rice with 150g chicken breast, or a sports recovery drink with a sandwich. Include a pinch of salt to enhance sodium absorption and rehydration. Follow up with a balanced dinner 2–3 hours later.

Bonking occurs when liver and muscle glycogen deplete. Prevent it by: (1) loading carbs 2–3 days before the race (7–12g per kg daily), (2) eating a substantial carb-rich breakfast 3–4 hours before the start, (3) consuming 30–60g carbs every hour during the race (sports drink, gels, bars, or real food), and (4) sipping electrolyte fluid consistently to maintain blood glucose. Train your gut to tolerate high carb intake during long runs so race day feels natural. Most athletes who bonk underestimated their fuel needs or suffered gastrointestinal issues—both are preventable with proper planning and testing.

For events under 60–90 minutes, your muscle glycogen is typically sufficient if you're well-fed in the days leading up to the event. Skip aggressive carb-loading; instead, maintain normal 5–8g carbs per kg daily and eat a standard pre-race meal. Intra-race fueling isn't necessary for most athletes in sub-90-minute efforts, though some may benefit from a sports drink or small gel for mental energy. Focus on pre-event hydration and sodium balance instead. Carb-loading shines for marathons, 70.3 triathlons, half-marathons, and longer events where glycogen depletion is a real risk.

Ultra-endurance (8+ hours) requires aggressive sodium replacement to prevent hyponatremia and maintain plasma volume. Aim for 300–700mg sodium per hour (or 0.5–0.7g/hour), consumed as part of your carb intake via sports drinks, salted gels, or electrolyte capsules. Stay below 800ml fluid per hour to avoid overhydration. Potassium and magnesium matter too—electrolyte supplements containing multiple minerals may reduce cramping. Test your plan in training; some athletes tolerate whole foods (salted nuts, pretzels) better than supplements. The goal is consistent fluid and sodium intake every 30–45 minutes, not bolus dosing.

Fat-adaptation (low-carb training) can improve fat oxidation efficiency in aerobic zones, potentially sparing glycogen during moderate-intensity sessions. However, high-intensity work and racing still demand adequate carbohydrate availability—even fat-adapted athletes carb-load for competitive efforts. A middle-ground approach: maintain carb availability for high-intensity workouts (intervals, tempo runs, speed work), but allow some training sessions to occur in a lower-carb state to enhance fat-burning capacity. This periodized approach balances glycogen sparing with performance on demand. Never low-carb approaching a major race.