Key Topics Covered

This episode is co-hosted by Samantha Staines, an Accredited Practising Dietitian and co-owner of the Runner’s Blueprint. We are going to unpack several topics relating to nutrition for marathon runners.

Intra-Race/Training Carbs

  • During endurance activities, carbohydrates are essential to maintain energy and delay fatigue.
  • Athletes often aim for 30-60g of carbs per hour for moderate-intensity sessions lasting 1-2 hours.
  • For longer events, like marathons, 60-90g per hour can be effective, and some athletes even tolerate up to 120g per hour.
  • Ideal carb sources include gels, sports drinks, and easy-to-digest foods.

Carb Loading

  • Carbohydrate loading helps maximise glycogen stores for optimal endurance performance.
  • The goal is usually to increase daily carb intake to 8-12g per kg of body weight 1-3 days before a race, prioritising familiar, low-fibre carbohydrate sources to reduce digestive discomfort.
  • Sticking to normal hydration and avoiding new foods or drastic changes ensures you’re well-prepared for your race without risking GI issues.

Electrolytes

  • It makes sense to use electrolytes for longer events where you are replenishing >70% of fluid losses.
  • For shorter durations, it can help with water uptake & staying well hydrated.
  • 300-600mg of sodium/hour is a good guide.

Hydration

  • Hydration strategies are highly individual and influenced by sweat rate, environment, and intensity.
  • Monitoring your hydration status—using urine colour as a basic guide or weighing pre- and post-training—is beneficial.
  • Drinking to thirst during training and racing is a safe strategy to prevent overhydration or dehydration, which can impair performance and increase cramping risk.

Caffeine

  • Caffeine can improve endurance performance by reducing perceived exertion and increasing alertness.
  • Many athletes benefit from 1-3 mg of caffeine per kg of body weight, taken 30-60 minutes before exercise – but also during/towards the end of a race can be helpful.
  • It’s important to trial caffeine use during training sessions to assess tolerance and avoid any adverse effects like jitters or GI discomfort on race day.

Body Composition 

  • Optimising body composition for endurance sports often involves balancing muscle mass with lean body weight for performance.
  • Focusing on protein intake, particularly during training cycles, supports muscle recovery without excessive gains. Keeping energy intake sufficient to support training demands is key for injury prevention and peak performance.
  • It is difficult to maintain a calorie deficit whilst enduring long training sessions, covering a lot of kilometres.
  • Becoming too lean can become an issue when red flags such as low energy availability become prevalent.
  • Low energy availability has an effect on bone health, immune health, gut health and menstrual health.

Beetroot Juice

  • Beetroot juice is rich in nitrates and is linked to enhanced endurance performance by improving blood flow and reducing oxygen costs.
  • For best results, athletes often take it 2-3 hours before exercise, but individual response can vary.
  • Glycerol is less commonly used due to complex dosing and potential GI issues, though it can support hydration in hot conditions.

The Runner’s Blueprint

Aidan Muir (APD), Nick Carbone (Exercise physiologist) and Samantha Staines (APD) all own The Runner’s Blueprint. The Runner’s Blueprint provides running and nutrition plans for anyone who has a general interest in running, all the way up to the top end of advanced/ competitive endurance races. These plans are tailored to each individual to ensure they feel their best whilst running and during races so that they can smash personal bests, feel adequately fuelled on their runs and during their races and for individuals who want to enhance their performance.

Relevant Blogs/Research

Relevant Blogs:

Nutrition for Endurance Athletes: Everything You Need to Know