Carbohydrate, stored in the body in the form of liver and muscle glycogen, is metabolised quickly and makes up the majority contribution to overall energy production when working at the intensities required during marathon running.
In this way, carbohydrate can be considered the preferred fuel for marathon day. However, our body has limited capacity to store glycogen. To maintain performance throughout the 26.2 miles it is important to maximise carbohydrate availability through pre-race and in-race nutrition strategies.
Practicing these pre-event and in-race nutrition strategies in training is essential through targeted long-runs. This allows the body to adapt to the challenges of carbohydrate loading and taking on carbohydrate while running, training the gut to tolerate this.
As it relates to daily and sports nutrition, everything you plan to do on marathon day should be mirrored for weekend long runs, including carbohydrate loading the day(s) prior, pre-event breakfast, in-race fuelling and post-race recovery.
The goal of carbohydrate loading is to maximise glycogen stores through the strategic manipulation of nutrients in the 24-48 hours leading into marathon day. Highcarbohydrate food sources should be prioritised, minimising fat, fibre and protein intake on these days. This short-term dietary periodisation can increase energy stores without excessive full or bloated feelings and shouldn’t simply be viewed as an eat everything strategy. Aim for 8-10g of carbohydrate per kilo body mass per day of your carb-load, this would be 560-700 grams of carbohydrate per-day for a 70 kg runner. Good food options for these days include: pasta, bread, rice, cereals, potatoes, energy bars and sports drinks.
Breakfast acts as a key meal ahead of the marathon to ensure you are fully fuelled for the start line. Travel, race-day stress and logistics can cause other distractions on marathon day, so knowing what you’re going to eat and being comfortable with this is going to get you to the start line in the best shape. Breakfast should include normal breakfast food: cereals, toast, bagels, jam, fruit juice. Providing 2-3 grams of carbohydrate per kilo body mass (i.e. 140-210 grams for a 70 kg runner) and be 2-4 hours before the start to allow for full digestion, minimising chances of gastrointestinal distress while running. A small protein source, such as Greek yoghurt or eggs could be included, but as with carbohydrate loading, fat and fibre should be restricted at breakfast.
Alongside fuelling, hydration is a key consideration during exercise performance, and you should always aim to commence running in a hydrated state. Through the morning of the marathon, drink 5-10 ml of fluid per kilo body mass, 350-700 ml of fluid for a 70 kg runner. This can be split between water and fruit juice with breakfast, then a carbohydrate-electrolyte sports drink as you travel to the event. Monitoring urine volume and colour is an effective method to ensure you are hydrated before the start but not excessively.
A limiting factor in marathon performance is glycogen depletion, and as such, fuelling while running is key. This should start in the first hour – if you wait until you are tired, or energy levels begin to drop, this is often too late to start re-fuelling. Aim to take in 60-90 g of carbohydrate per hour of running. Alongside fluid intake, an hour of energy could be 3x Isotonic Energy Gels. Utilise caffeine gels towards the last hour of the race when tiredness and fatigue is likely to be highest.
While running your body heats up. To keep body temperature at an optimal level, water is drawn from blood plasma and secreted from pores in the skin, as sweat. While this mechanism aids thermoregulation, excess fluid and electrolyte loss can have a negative impact on exercise performance. Aim not to lose more than 2-3% of your body mass via sweat loss. This usually means consuming 500 ml of fluid per hour depending on sweat rate, temperature and humidity – drinking additional fluids as needed. Taking little and often from each water station is advisable versus waiting until you are thirsty and having large volumes of fluid. Water alone is not enough, electrolytes too need replacing. Overall nutrition for marathon running should include electrolyte containing energy gels or fluids.
Marathon running depletes muscle glycogen stores, causes muscle damage and results in fluid loss. Your recovery nutrition should therefore focus on both carbohydrate and protein intake to replenish muscle glycogen and repair muscle damage. Fluid and electrolytes should be provided to aid rehydration. REGO Rapid Recovery Plus can be used within 30-60 minutes of finishing a marathon to meet these needs and kick-start the recovery process, having a full meal of carbohydrate, protein and vegetables 2-3 hours later.