Nutrition Tips for Endurance Athletes

Many sports and events like running, cycling, swimming, soccer and many more are thought of as endurance activities because of their long duration. Although some of these events last less than an hour, others continue for hours, or days. Each endurance event has its own unique duration and challenges. For this reason, they have their own set of nutrition requirements for energy-yielding nutrients and fluids.

But what are the best nutrition practices for an endurance athlete before, during, and after a competition? This excerpt from Nutrition for Sport, Exercise, and Health Second Edition will provide you with some of the tips and key information on how nutrition can be applied to endurance activities.

Carbohydrate Loading

Maximizing glycogen reserves before an endurance event is a very common strategy among athletes. The theory is that if a person can deplete glycogen with exercise followed by repletion with a high-carbohydrate diet, then more glycogen will be stored than if the person maintains an exercise routine and consumes a steady amount of carbohydrate. Carbohydrate loading is an effective strategy for endurance events lasting 90 minutes or more if implemented at least 24 hours before the event. Distance runners, road cyclists, cross-country skiers, and open-water swimmers are the type of athletes who may benefit most from this particular strategy

Research suggests that performance can be improved by approximately 2 to 3 percent when glycogen stores are super compensated, as compared with having normal stores. However, keep in mind that every gram of stored glycogen also retains 3 to 4 grams of water. Therefore, glycogen-loading protocols can induce a gain in body weight of up to 2 kilograms (4.4 lb), which might cause the athlete to feel weighed down before the event. It is up to the athlete whether they will be able to perform well with the extra body weight caused by glycogen-loading.

There are various ways of carbohydrate loading. The main goal here is to increase carbohydrate availability for the later stages of an event. The objective can be achieved by tapering training volume a few days before an event and gradually increasing carbohydrate intake to the desired quantity. It is also possible, for an athlete to consume a high-carbohydrate diet for 3 days before competition, taper their exercise the week before and rest completely the day before.

Day of an Event

Pre-competition intake the day of an event is critical for optimal performance. Athletes should prepare for an event by consuming enough food to avoid hunger, provide adequate fuel and fluids, and load their glycogen stores while minimizing the risk for gastrointestinal (GI) distress. Carbohydrate and other nutrient intake will vary depending on factors such as type of event, time of event, environmental conditions, physiological training status of the athlete, stress of the athlete, and individual preferences. There is no one pre-competition meal that is best for everyone. Many athletes prefer to begin an endurance event with full glycogen stores. However, other athletes might choose a different approach.

Most research in this area has been on endurance athletes whose sport involves continuous movement, but it might also apply to those who participate in sports that include intermittent high-intensity periods, such as football. Carbohydrate ingestion before an event will likely be beneficial for prolonged, sustained, or intermittent activities lasting an hour or longer and for those who have not eaten for several hours before an event. For shorter events, adequate glycogen stores will likely be enough

In order for an athlete to tolerate this meal well, it should consist of low-fat, low-fiber and a little protein, depending on the event’s intensity and duration. Since fluids are also very crucial, consuming a carbohydrate-containing beverage along with the meal may be preferred if carbohydrate needs cannot be met through food alone.

Each athlete should experiment their intake amounts before competition. Generally, a small meal or snack with a beverage is sufficient, but all athletes are different and must find what works best for them. Some athletes need to have a little solid food in the stomach, some athletes do not tolerate anything solid and prefer a beverage only. Jitters before a competition can also affect how athletes respond to food and fluids. However, this circumstance is harder to replicate in practice and which might make it hard to prepare for.

Minimizing Gastrointestinal Distress for Athletes

The following tips can be helpful for endurance athletes to prevent or minimize GI distress. But if an athlete has a diagnosed medical condition like celiac disease, irritable bowel syndrome, or Crohn’s disease, which requires medical nutrition therapy, a referral should be made to a registered dietitian familiar with these conditions.

Avoiding high-fiber foods during the day, or even days, before competition. On all other days, consuming adequate fiber in a diet will help keep the bowel movements regular and helping decrease the likelihood of constipation.

Consuming high-fructose foods with caution, especially drinks that are very high in fructose. Beverages containing both fructose and glucose might be better tolerated.

Trying not to eat within 3 hours of competition if you have a sensitive stomach.

Avoiding dehydration by starting the event sufficiently hydrated and consuming fluids throughout the event. Avoiding overhydration in this stage is important too.

Not consuming concentrated carbohydrate-containing beverages.

Practicing new nutrition strategies several times before implementing them during competition to test the reaction of your body.

Macronutrient Intake After an Event

For athletes who train or compete hard on multiple occasions on the same day or on consecutive days, glycogen replacement is crucial. When sufficient carbohydrate is consumed, glycogen stores replenish at a rate of 5 to 7 percent per hour, and they take 20 to 24 hours to re-establish.

Without a purposeful modification to a certain dietary pattern, glycogen will eventually replenish with enough carbohydrate intake. But this process might take time and might not maximize glycogen stores in between high endurance activities. Therefore, this method is not ideal for an athlete that needs to train or perform again within 24 hours.

Gaining back the depleted glycogen stores are even more important if subsequent training or an event takes place within several hours of the first activity period. In this case the athlete should begin to intake carbohydrate as soon after activity as possible to maximize glycogen stores for the next session.

An important note is that the form of carbohydrate might not be as important as the amount. Because glycogen can be replenished equally well with both liquid and solid carbohydrates. For this reason, the primary determinant at this point should be athlete’s personal preferences.

As a general rule of thumb, recommended amount of carbohydrate should be consumed immediately after exercise to make the most out of the enhanced metabolic window for a fast glycogen replenishment. The best practice is to follow this with repeated consumption at frequent intervals (e.g., 1.0–1.2 g/kg each hour) for the first 4 hours and then resume normal intake until daily targets are met. Delay of carbohydrate intake for as little as 2 hours after an exercise might cause the athlete to miss the window of opportunity and not maximize glycogen stores before the next event. Again, this protocol is important for multiple-day or consecutive-day training or events such as long road bicycle races (e.g., Tour de France, La Vuelta), back-to-back competitions, but not as important if there is no need to optimize glycogen stores rapidly like a single marathon race.

Figure 1: An overview of carbohydrates that should be consumed throughout the day with consideration for training schedules and recovery times.

There are a lot of nutrient requirements for endurance athletes when it comes to energy, fat, carbohydrates, and fluids, and it can be difficult to translate these requirements into actual food choices. In modern day sports, wide selection of foods, beverages, and supplements are readily available. Various alternatives significantly assist endurance athletes in meeting the unique nutrition needs of their chosen sport.

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