Sports nutrition: what to eat before and after running

Achieving peak performance in road races requires discipline, resilience and, of course, a nutritional strategy. Whether you are a high-performance athlete or someone who runs for pleasure, what you put on your plate can directly influence your energy during the course, training performance and recovery.

That is why understanding what to eat before and after running is an essential part of preparation. After all, to expend energy, you must first provide it to the body—but how and when? 

In sports nutrition for endurance disciplines, known as endurance, meal planning is not a mere detail: it helps prevent early exhaustion and promotes more efficient physical recovery. However, the ideal plan depends directly on the length of the course, since short runs and long-distance training require completely different energy-fueling strategies. Check it out!

Browse the content:

• How does the body respond during a run?
• What should you eat before running, according to studies?
• Between 1 and 4 hours beforehand
• Long-distance runs (more than 60 to 90 minutes)
• Short runs (up to 75 minutes)
• Between 30 and 60 minutes beforehand
• Long-distance runs (more than 60 minutes)
• Short runs (less than 45 to 60 minutes)
• Attention: do not test anything on race day
• What should you eat after running?
• “Repair” requires special attention

How does the body respond during a run?

During a run, blood is directed primarily to the active muscles, which can reduce blood flow to the gastrointestinal system by up to 80%, according to a study published in the scientific journal Sports Medicine. This drop in blood supply, known as ischemia, compromises the intestine’s protective barrier. Trying to digest heavy or fatty meals, a large amount of protein or foods rich in fiber can trigger gastrointestinal discomfort, as these substances slow gastric emptying. The study estimates that between 30% and 90% of endurance runners experience these problems, making intestinal discomfort the most common cause of declining performance and dropping out of long-distance events.

What should you eat before running, according to studies?

To prevent pain and ensure a steady supply of energy, science recommends planning the meal based on the duration and intensity of the effort.

Between 1 and 4 hours beforehand

Given how the body functions, the recommendation is to eat within a timeframe that is comfortable for metabolism—between one and four hours before running—in accordance with the official guidelines of the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine. However, strategies differ for short- and long-distance runs.

Long-distance runs (more than 60 to 90 minutes)

The meal eaten 1 to 4 hours before running is essential for replenishing glycogen stores. It should prioritize easily digestible, carbohydrate-rich foods, accompanied by a moderate serving of protein, low fat and low fiber to prevent gastrointestinal discomfort during exercise. 

For events lasting more than 90 minutes, a carbohydrate-loading strategy is also recommended 36 to 48 hours before the event, consuming 10 to 12 g of carbohydrates per kilogram of body weight per day.

Short runs (up to 75 minutes)

For short runs, there is no need to maximize carbohydrate stores, since usual daily reserves are already sufficient to fuel the effort. If the workout is intense, such as 45- to 75-minute speed intervals, eating solid foods during this window may even feel heavy on the stomach. 

According to the same guidelines, the amount of carbohydrates specifically recommended for this pre-workout meal, when needed for higher-volume training, ranges from 1 to 4 grams per kilogram of body weight (1 to 4 g/kg). Total daily carbohydrate intake varies according to training load and the effort required by the athlete’s routine, as detailed in the table below, although it is also essential to assess each individual’s profile. 

Source: Data compiled from the joint position statement “Nutrition and Athletic Performance” (AND/DC/ACSM) 

Between 30 and 60 minutes beforehand

If a person still feels the need for an additional meal closer to training or competition, or has not had time to plan what to eat, they can have a snack about 30 to 60 minutes beforehand. However, this also varies according to the race distance.

Long-distance runs (more than 60 minutes)

Options should be easy to digest and low in fiber and fat, such as a very ripe banana, which contains little resistant starch (the fraction of starch that is not digested in the small intestine), two slices of white bread with jam, Brazilian cassava starch crackers, or palatinose/carbohydrate gel accompanied by water, as these provide the necessary energy without causing gastrointestinal discomfort. 

Short runs (less than 45 to 60 minutes)

For runs lasting less than 60 minutes, a last-minute snack is generally unnecessary if the person has eaten properly throughout the day. Eating solid foods too close to a short run can cause unnecessary gastric discomfort due to reduced blood flow to the digestive system. An alternative strategy for short, intense workouts is to perform a carbohydrate mouth rinse (mouth rinse)—using standard sports drinks or solutions formulated with carbohydrate mixtures such as glucose and fructose—immediately before running. According to the joint position statement on Nutrition and Athletic Performance, “frequent contact between carbohydrates and the mouth and oral cavity can stimulate parts of the brain and central nervous system to improve perceptions of well-being and increase physical performance.”

Attention: do not test anything on race day

Nutritional strategies and new foods should be tested and simulated during regular training, never on competition day. Consistently following the meal plan to which the body is accustomed in the weeks leading up to the event protects runners from intestinal problems and ensures the planned performance.

What should you eat after running?

If pre-workout nutrition is about mobilizing energy, post-workout nutrition is about rebuilding, rehydrating and regenerating. This is the phase in which supercompensation occurs—that is, the body’s adaptation that makes the athlete stronger and more resilient for the next challenge. For efficient recovery, sports nutrition should be based on the “3 R’s” protocol:

1. Rehydrate: replace the fluids and electrolytes (minerals that help regulate fluid levels in the body) lost through sweat. For short runs without extreme exertion, rehydrating with regular water is sufficient. However, after long runs or on very hot days, the recommendation is to consume 1.25 to 1.5 liters of fluids for every kilogram of body weight lost during training, prioritizing drinks or foods containing sodium to help the body retain water. 
2. Refuel: restore muscle glycogen stores—the way the body stores carbohydrates in the muscles for use as an energy source during exercise. The urgency and amount of refueling depend on the run: during short or light workouts, when energy stores are not completely depleted, replenishment can be flexible throughout the day through regular meals. However, after long runs or if the person has another training session in less than 8 hours, it is vital to consume 1 to 1.2 g/kg/hour of carbohydrates during the first 4 to 6 hours after exercise to accelerate energy recovery 
3. Repair: provide essential amino acids to synthesize new muscle proteins and repair the microtears caused by the impact of each stride. Regardless of whether the run was short or long, consuming 0.25 to 0.3 g/kg of high-biological-value protein, such as that found in beef, immediately after the activity maximizes protein synthesis and accelerates muscle recovery.

“Repair” requires special attention

In addition to muscle rebuilding and hydration, the repair stage requires special attention to the integrity of blood cells. Runners are more likely to develop iron loss through impact hemolysis (the destruction of red blood cells caused by the repeated impact of the feet on the ground), according to studies regarded as references in sports nutrition. Although this destruction is more pronounced during long-distance, high-volume training, runners of all levels and distances should be aware of this loss. Therefore, proper post-workout nutritional replenishment should also focus on preventing anemia and supporting microvascular health.

However, it is always worth remembering that not all iron is the same. Heme iron, found in hemoglobin and myoglobin, is obtained primarily from beef, pork, poultry and fish; its absorption is much more efficient (more bioavailable) than that of non-heme iron, found in plant-based foods such as beans, lentils and broccoli.

To maximize absorption, the timing of red meat consumption should take the training schedule and the body’s natural rhythm into account. According to a guideline published on the scientific platform Nutrition X, the hormone hepcidin, which blocks iron absorption, is naturally lower in the morning. In addition, physical exercise triggers a peak in this hormone 3 to 6 hours after exertion. Therefore, the scientific recommendation is to consume a serving of red meat preferably in the morning, when the natural blockage is lower, or, if the person trains at other times, as close as possible to the end of the activity—ideally within the first 30 minutes—to ensure mineral absorption before the post-workout hormonal peak occurs. 

Since each body requires specific amounts of carbohydrates, protein, hydration and micronutrients such as iron, it is essential to seek professional guidance to determine ideal portions according to age, weight, height, health history and running discipline. Caution is never excessive, and the streets should always be taken by dedicated and responsible individuals, ensuring that the finish line is reached only when the tape breaks.