Finishing a marathon is not only about the miles you log in training. What you eat and drink before, during and after the race directly affects your performance, your ability to sustain pace and your recovery. Recent studies on runners at the Seville Marathon show that those who consume 60–90 grams of carbohydrates per hour are more likely to break the three-hour barrier, while a poor fueling strategy can ruin months of preparation. Below you’ll find a practical guide to planning your marathon nutrition efficiently.
Nutrition Planning in the Days Before the Marathon
In the 72–48 hours before race day, focus on replenishing glycogen stores without overeating to the point of digestive discomfort. The general recommendation for marathon runners is to consume 8 to 10 grams of carbohydrates per kilogram of body weight per day, while keeping protein around 1.2–1.7 g/kg and fats at moderate levels. This does not mean “endless pasta loading,” but rather choosing complex, easily digestible carbohydrate sources.
- Two to three days before the race, slightly increase your intake of rice, pasta, potatoes, bananas, white bread and oats.
- Combine medium glycemic index foods (pasta, bread, rice) with faster-absorbing options (honey, sports drinks) after long training sessions.
- Maintain consistent hydration throughout the day with water and electrolytes; avoid alcohol and very fatty meals.
- If well tolerated, include small portions of lean proteins (chicken, fish) and healthy fats (olive oil, avocado) to promote satiety without overloading your digestive system.
In the final 24 hours before the marathon, prioritize simple carbohydrates and reduce fiber intake. A dinner of white rice with a small portion of chicken, or boiled potatoes with banana and yogurt, can work well. Avoid spicy sauces, raw vegetables and whole-grain foods that may cause gastrointestinal discomfort.
Race Morning Breakfast
Your race-day breakfast should be eaten two to four hours before the start and provide approximately 1–4 g of carbohydrates per kilogram of body weight (around 80–150 g for most runners), along with moderate amounts of protein and fat to stabilize blood sugar levels. A bowl of oatmeal with honey and nuts, toast with jam and banana, or rice pudding are simple and effective examples. Pair breakfast with 500–700 ml of water or an electrolyte drink to arrive at the start line properly hydrated.
Thirty to sixty minutes before the race, you may have a light snack that you have already tested in training, such as a gel, half a banana or carbohydrate gummies. Avoid experimenting with new foods at this stage, as your digestive system will already be under stress.
Fueling During the Marathon
During the race, the goal is to maintain stable blood glucose levels and delay fatigue. Most research recommends consuming between 30 and 60 g of carbohydrates per hour, although well-trained runners can tolerate up to 90 g/h to maximize performance. This requires gut training and careful planning of aid station strategy.
- Split intake into small, regular doses: take a gel or about 200 ml of sports drink every 30 minutes instead of consuming large amounts at once.
- Combine fast-absorbing sources (gels, glucose-based drinks) with slightly slower options (maltodextrin chews, ripe banana) to avoid sharp glucose spikes.
- Aim for 200–500 mg of sodium per hour through sports drinks or salt capsules to replace electrolytes lost in sweat.
- Practice this strategy during long runs; your digestive system needs to adapt to metabolizing carbohydrates while running.
- Avoid drinking excessive amounts of plain water without electrolytes, as this may increase the risk of hyponatremia. Alternate water with electrolyte drinks or sodium-containing gels.
Hydration and Electrolytes
Water is essential for thermoregulation, nutrient transport and waste removal. During a marathon you may lose between 1 and 3 liters of sweat per hour, depending on temperature and effort level. The following guidelines can help you stay safely hydrated:
- Perform a sweat test during training: weigh yourself before and after a long run. Every 1 kg of body weight lost equals approximately 1 liter of fluid that should be replaced.
- Drink 400–700 ml of fluid per hour, adjusting according to your sweat rate and environmental conditions.
- Include sodium in your drinks. Some endurance formulas provide around 300 mg of sodium per 350 ml, but you can also prepare a homemade sports drink with water, lemon juice, a pinch of salt and sugar.
- Start hydrating the night before and drink two glasses of water with minerals upon waking. After the race, aim to consume approximately 125–150% of the body weight lost in fluids to ensure full rehydration.
- Do not rely solely on thirst. The thirst mechanism typically activates after you have already lost around 2% of your body weight, which can negatively affect performance.
Post-Marathon Recovery Nutrition
The marathon does not end at the finish line. The first 30–60 minutes represent a key metabolic window to replenish glycogen and repair muscle tissue. Current recommendations suggest consuming 1.0–1.2 g of carbohydrates per kilogram of body weight and 20–30 g of high-quality protein within the first hour. A smoothie made with milk or plant-based drink, protein powder, oats and banana is a quick and effective option; yogurt with fruit and honey or a turkey and fresh cheese sandwich also work well.
Over the next 24–72 hours, continue consuming quality carbohydrates (rice, quinoa, vegetables, fruits), lean proteins and healthy fats to optimize recovery and restore energy reserves. Prioritize sleep and avoid intense training loads until you feel fully recovered. Ongoing hydration remains essential—include water with mineral salts and electrolyte drinks to replenish what was lost during the race.
Train Your Gut
Many runners struggle to tolerate more than 30 g of carbohydrates per hour during a race. However, intake capacity can improve with adaptation. So-called “gut training” involves practicing carbohydrate intake during at least one or two weekly training sessions.
- Start consuming carbohydrates 15–20 minutes into a long or intense training session.
- Gradually increase intake toward 60–90 g/h, tracking sensations and any gastrointestinal discomfort.
- Use the same products you plan to consume on race day (gels, chews or drinks) to avoid surprises.
- Remember that proper hydration and sodium intake enhance carbohydrate absorption; dehydration reduces intestinal efficiency.
- Practice caffeine intake as well if you plan to use it, as it may increase fat oxidation and improve perceived effort.
Final Thoughts
A well-designed nutrition strategy is just as important as a solid training plan. Proper carbohydrate loading, effective hydration and gut training will help you run faster and recover better. Every runner is different, so test these strategies in training and consult a sports nutrition professional if needed.
Beyond nutrition, complement your preparation with strength training and techniques that improve running economy. On our blog, you can find resources such as our complete guide to strength training for runners and our Seville Marathon 2026 guide, where we discuss race strategy and planning for fast marathons. Integrate this knowledge into your routine and enjoy the journey.
Finally, with SnapRace you can monitor your training sessions, track your gels and hydration strategy, and analyze how they impact your performance. Download the app and become the most informed runner on the start line.