Nutrition tips for the half marathon

Nutrition guide for the half marathon: optimizing performance and recovery

Preparing for a half-marathon presents a unique challenge in the career of a long-distance runner. Situated at the intersection of the sustained intensity of short-distance races and the pure endurance of the marathon, this event demands a level of physiological and nutritional rigor that is often underestimated.

While physical training builds the engine, nutrition provides the essential fuel to avoid premature depletion of glycogen reserves, a phenomenon that frequently occurs around the fifteenth kilometer. Precise nutritional management not only helps maintain a stable target pace, but also prevents gastric and muscular disorders that compromise performance.

Analysis of best practices and current data underlines that nutrition must be approached as an integral component of preparation, starting several weeks before the start and extending well beyond the finish line.

The physiology of exertion over 21.1km

To understand the importance of a nutritional strategy, it is necessary to analyze the energy mechanisms involved during a half-marathon. At a running intensity close to the anaerobic threshold, the body prioritizes the oxidation of carbohydrates as its primary energy source. The human body has limited stores of glucose, mainly stored as glycogen in the liver and skeletal muscles.

The dynamics of glycogen and blood glucose

The total glycogen store in a trained adult is approximately 500g, which represents about 2000 calories. During intense exertion lasting more than an hour, these reserves inevitably become depleted if no external input is provided. The drop in glycogen levels leads to a decrease in muscle contraction capacity and central nervous system fatigue. The refueling strategy therefore aims at two objectives: saturating stocks before the start by replenishing carbohydrates and maintaining blood glucose levels during the race to spare muscle glycogen for as long as possible.

The preparation: building a solid nutritional foundation

Performance nutrition isn't limited to the final days before competition. From the very beginning of the training plan, often six to eight weeks before the event, nutrition must support the workload and promote cellular recovery.

Balance of macronutrients and micronutrients

A balanced diet is based on a regular daily intake of protein for the repair of muscle fibers damaged by repeated impacts, starches for the daily renewal of energy, and quality lipids for hormonal and anti-inflammatory health. Consuming fruits and vegetables, at a rate of at least five portions per day, ensures the intake of vitamins and minerals essential for energy metabolism.

Hydration should be considered a lifestyle habit. Even mild chronic dehydration increases blood viscosity and places additional cardiac stress on every workout. The goal is to obtain clear urine throughout the day, a sign of a balanced fluid intake.

Digestive system training or Gut Training

The digestive system undergoes major stresses during running: reduced blood flow to the stomach and intestines in favor of the muscles, mechanical shocks and thermal stress. It is imperative to practice " Gut Training ", which consists of consuming gels, bars or energy drinks during long outings. This process accustoms the stomach and intestines to absorbing nutrients during exercise, thus reducing the risk of nausea or diarrhea on race day.

The week before the race: the saturation strategy

The seven days preceding the half-marathon are crucial for transforming the body into an optimal energy reserve. This period is divided into two distinct phases.

From D-7 to D-4: stabilization and transition

During this phase, training decreases in intensity and volume (tapering). The diet remains normal but balanced, taking care not to overconsume unnecessary calories despite the reduced activity. However, people are starting to favour lean meats and limit overly spicy foods or saturated fats that could make digestion difficult.

From D-3 to D-1: "Carb-loading" or carbohydrate loading

The goal is to radically increase carbohydrate intake to achieve maximum glycogen saturation. The recommendations are between 8 and 12g of carbohydrates per kilogram of body weight per day. To reach these levels without digestive discomfort, it is advisable to turn to carbohydrates with a low or moderate glycemic index such as white rice, "al dente" pasta or sweet potato, while drastically reducing fiber (raw vegetables, whole grains) which accelerates transit in an undesirable way.

The use of maltodextrin is particularly relevant here. This glucose polymer allows for an increased carbohydrate load without the excessive sweetness and without the satiety of a giant pasta meal. By consuming 30 to 60g diluted in water several times a day, the runner optimizes his reserves in a smooth and efficient way.

The morning of the race: the starting protocol

The pre-race meal is often a source of anxiety. Its main function is to replenish liver glycogen after the overnight fast and to ensure stable blood sugar levels without causing gastric discomfort.

The perfect breakfast and timing

Ideally, this meal should be finished 3 hours before departure to allow for complete gastric emptying. It should be rich in digestible carbohydrates, low in fats, fiber, and complex proteins. Classic options include white bread with honey or jam, a ripe banana, or an energy cake.

Coffee can be beneficial for concentration and fat mobilization, but its consumption should be moderate due to its diuretic properties and its potential to irritate the stomach in some individuals. Between the end of breakfast and departure, a waiting ration consisting of water or a very lightly sweetened drink can be consumed in small sips to maintain hydration without overloading the bladder.

Fueling strategy during the half marathon

A 21.1-kilometer race requires active management of fluid intake to compensate for the loss of minerals through perspiration and glucose consumption. Consistency is key: waiting until you feel thirsty or fatigued means you've already become deficient and it's too late.

Hydration: beyond pure water

Water alone is not enough during prolonged exertion beyond 1 hour 30 minutes. Sweating leads to a massive loss of electrolytes (sodium, potassium, magnesium). Drinking only water in large quantities can cause hyponatremia, that is, a dangerous dilution of mineral salts in the blood. It is therefore recommended to consume 150 to 250ml of liquid every 15 to 20 minutes.

The use of an isotonic drink is recommended. Its carbohydrate (between 4% and 8%) and electrolyte composition allows for rapid intestinal absorption and effective cell rehydration. For more details on this topic, it is highly recommended to consult the marathon hydration guide. , which details the ideal mineral ratios for endurance sports.

Energy intake: gels and compotes

The standard recommendation for a half marathon is an intake of 30 to 60g of carbohydrates per hour. This amount can vary depending on the runner's weight and the intensity of the effort.

• Energy gels : They offer a high concentration of sugar in a small volume. Mulebar favors a natural approach, using brown rice syrup for a rapid glucose boost and agave syrup for a more gradual release of natural fructose (glycemic index of 15). This combination avoids the "yo-yo" effect of blood sugar and sudden drops in energy levels. Mulebar energy gels are also the only ones that are truly resealable, allowing you to consume them in 3 or 4 servings—that makes all the difference. It's essential to drink water after taking the gel to rinse your mouth, dilute the sugar in your stomach, and speed up its absorption into the bloodstream. To choose the right product, see the article on which energy gels are best for marathons. offers a thorough comparative analysis of the different textures and flavors.

• Energy compotes : For those who find gels too sickening or too sweet, energy compotes offer a slightly more substantial fruity texture. They are particularly easy to digest and provide a more natural feeling of fullness without weighing down the stomach. Their resealable packaging with a cap also allows them to be consumed in several portions to avoid a sudden sugar rush.

• Energy bars : While more common in longer events like trail running, small bites of bars can be eaten at the start of a race if the expected time is over two hours. However, it's still difficult to chew while running.

How much should I consume during a half-marathon?

 

The importance of minerals and electrolytes in performance

Endurance performance is inextricably linked to mineral balance. Electrolytes are not simply additives, but catalysts for biochemical reactions.

• Sodium : This is the mineral most lost through sweat. It maintains plasma osmotic pressure and helps prevent hyponatremia.

• Potassium : Essential for nerve impulse transmission and muscle contraction. Its deficiency is a common cause of early fatigue.

• Magnesium : It plays a key role in the production of ATP (energy) and promotes muscle relaxation, thus limiting the occurrence of painful cramps.

• Calcium and Zinc : Although lost in smaller quantities, they contribute to bone strength and protein metabolism during prolonged exertion.

Mulebar products incorporate these mineral salts in a balanced way in their drinks and gels, often using ingredients naturally rich in these nutrients rather than synthetic additives.

Recovery: tomorrow's training starts now

Once the finish line is crossed, the body is in a state of significant oxidative stress, with low energy stores and partially degraded muscle fibers. Nutritional recovery should be structured around three main axes, often summarized by the "3 Rs": Rehydrate, Recharge, Repair.

The metabolic window

This is the period of approximately 30 to 60 minutes after exertion when glucose transporters and protein synthesis mechanisms are hyper-activated. Taking advantage of this metabolic window allows for a considerable acceleration of the return to normal (homeostasis).

1. Rehydrate : Drink water rich in bicarbonates and sodium to compensate for losses and neutralize the acidity produced by intense effort.

2. Refuel : Provide fast carbohydrates (fruits, compotes, juices) to immediately restart glycogen resynthesis.

3. Repair : Consume approximately 20g of high-quality protein (eggs, plant-based protein, dairy products) to stop catabolism and repair muscle micro-tears.

A specific recovery drink, combining carbohydrates and proteins in a ratio of 3:1 or 4:1, is the most practical tool to cover these needs immediately after the race.

The Mulebar approach: naturalness and eco-responsibility

In a market saturated with ultra-processed sports nutrition products, Mulebar stands out with a philosophy focused on ingredient quality and respect for the environment.

100% natural ingredients for easy digestion

Mulebar gels and bars contain no artificial preservatives, colours or flavours. The energy base is based on natural cereal syrups (brown rice) and agave, offering a smooth texture and an authentic taste that does not overwhelm the palate during intense effort. This natural composition is the best guarantee against the stomach upsets often associated with synthetic products. It's also worth noting that all the recipes are formulated to create delicious products that provide a boost during strenuous activity.

Innovation and practicality: resealable tubes and eco-refills

A major innovation of Mulebar lies in its resealable and reusable gel tubes. Unlike traditional sachets that must be consumed all at once and leave pockets dirty, flip-top caps allow you to take your gel in several small sips, thus smoothing out the sugar intake and avoiding insulin spikes.

In addition, Mulebar offers 444g eco-refills, which is equivalent to 12 gels. This system allows you to fill your own containers (reusable tubes, silicone vials or soft flasks), offering a solution that is 33% cheaper than individual gels while significantly reducing the production of plastic waste on trails and roads.

Original and stimulating flavors

The brand offers unusual gel recipes, such as lemon-ginger (excellent for digestion), coffee (for the final boost) or salted caramel (sodium intake). This variety allows the runner to adapt their tastes throughout their preparation and competitions, avoiding taste fatigue.

Succeeding in a half-marathon requires a 360° vision where the plate and the water bottle are as important as the pair of running shoes. By understanding glycogen mechanisms, adopting a rigorous carbohydrate loading strategy and managing supplies with natural and tested products, the runner transforms a potentially painful event into a controlled performance experience.

Nutrition should never be a source of uncertainty on race day. It should be the foundation upon which the mental strength to cross the finish line rests, allowing you to feel the satisfaction of a job well done. By incorporating the advice in this guide and exploring the sustainable solutions offered, every athlete can give themselves the means to achieve their ambitions, whether it's for their first race or a new personal best.

 

Answers to frequently asked questions

What is the exact distance of a half-marathon?

A half-marathon measures precisely 21.0975 kilometers, which is exactly half the distance of an official marathon (42.195 km).

Is it difficult to run a half marathon?

The difficulty is relative to the level of training and the target time. It is a distance accessible to any regular runner capable of running 10 km without stopping, but it requires specific preparation of 8 to 12 weeks to be completed easily and without injury.  

What is the average time for a half marathon?

For an amateur runner, the average time is generally between 1 hour 50 minutes and 2 hours 10 minutes. Experienced runners often aim for the symbolic 1 hour 30 minute mark, while the world record is close to 57 minutes.

What should I eat 3 days before a half-marathon?

It's time to start replenishing your carbohydrate stores. Focus on "white" starchy foods (rice, pasta, steamed potatoes) and reduce insoluble fiber to avoid bloating. Hydration should be increased by 500ml per day compared to usual.

Should I take maltodextrin?

Maltodextrin is recommended to saturate glycogen stores without overloading the stomach. It is particularly useful in the last two days before the race, diluted in drinking water throughout the day.

How many gels should you consume during the race?

The classic strategy for a half marathon is to take two to three gels. A first one around the 7th kilometer, a second one around the 14th kilometer, and possibly a final "sabotage" at the 18th kilometer.

How to avoid digestive problems while running?

The main mistake is testing a new product on launch day. You should test each gel and drink during training, avoid fats and fibers the day before, and drink enough water with each serving of solid or semi-liquid food.

What is the best diet after a half-marathon?

Priority should be given to rehydration and glycogen replenishment. A snack combining carbohydrates and proteins (e.g., banana and yogurt, or a recovery drink) should be consumed within 30 minutes of arrival.