Nutrition for Endurance Sports – Introduction

Endurance sports are becoming more and more popular, and so is triathlon, one of its typical representatives, and currently the fastest growing sport in the world judging by the number of participants.

Sports in general can be divided into strength, endurance, and their combinations. A typical representative of strength sport would be weightlifting, and ultramarathon can typically represent endurance sports. However, most sports fall somewhere in between. For the needs of this article, the definition of endurance sport will be an activity of submaximal intensity that is longer than one hour.

Of course, training is the most powerful way to progress in sports – amateur or professional – and diet is an essential support system which can accelerate or decelerate the adjustment process and in some cases, prevent it. Someone smart once said:

Diet won’t make an average athlete Olympian, but it can make an Olympian average.

Athlete diet

In terms of content, athletes diet is no different than a diet of a non-athlete. Human body, regardless of physical activity, needs certain nutrients to function properly. Needs are different when it comes to quantity – the amount of these nutrients, which for athletes, can be several times higher.

If we differentiate between amateur and professional sports, we’ll see another difference, which is the timing of nutrient intake – a neglectable factor for amateur athletes, while it can mean a difference between first and tenth place for a professional athlete.

Seeking the best ways to improve results, athletes and their coaches often try various approaches to training, diet, and sometimes illegal practices. It’s very important to emphasize that diet during the activity (training and competition) is important for result optimization, but what’s even more important is the overall quality of the diet, including the time between two activities (the period of recovery).

Top athletes are popularly thought to be eating healthy, without exception. Because they look fit. Unfortunately, too often that is not the case. Many athletes with a lot of talent and work ethics succeeded not because of a certain diet but despite it.

Also, eating disorders are more common in athletes than non-athletes, (1) especially in sports where lower body weight is desirable – either because of the quality of performance (marathon) or aesthetics (figure skating). These disorders are more common in women than men. Copying a top athlete’s diet is mostly pointless and sometimes even harmful. As an example I’d like to mention Novak Djokovic who, supposedly for health reasons, follows a gluten- and lactose-free diet. This type of diet won’t have a positive effect on your health unless you have celiac disease (or gluten intolerance, which existence is still being heavily disputed) and milk allergy (or lactose intolerance). Also, it can have a negative effect if you do not replace the excluded nutrients through other food sources.

Athletes in strength sports have always been focusing on protein intake, and endurance sports have been focusing on carbs – but both of these often neglected other macronutrients without any reason. This can lead to dietary imbalance and decelerated progress.

Athletes, especially those in endurance sports where diet has a bigger influence on progress, need to be educated on benefits of proper diet and its role in training process, competition preparation, and during these. These educations need to be held by professionals (nutritionists) and not, as is often the case, by conditioning coaches or physical therapists who have only basic knowledge on nutrition and metabolism. Unfortunately, sports nutrition is not a regulated trade, allowing unqualified individuals to pursue it, which leaves many athletes with low quality information These sources include media and supplement industry brands, which try to use athletes’ readiness to invest money for optimization of results.

Individual approach

I cannot emphasize enough the need for individual approach to every athlete. Guidelines need to be exactly as their name says – guidelines. Athletes’ needs have to be determined on an individual level, taking into account both physical and psychological characteristics as well as external factors. Dietary needs of athletes are not static, they vary on a monthly, weekly, and even daily basis, depending on the preparation cycle.

After this very general introduction, in the next  article I will discuss the basics of metabolic processes in endurance sports, daily needs of endurance athletes, and explain briefly main causes of fatigue and drop in performance intensity. Then, following articles will discuss nutrient intake just before, during, and after the activity, including the explanation of whether the most common dietary supplements promising performance improvement actually (do not) work.


  1. Sundgot-Borgen, Jorunn, and Monica Klungland Torstveit. “Prevalence of eating disorders in elite athletes is higher than in the general population.”Clinical Journal of Sport Medicine 14.1 (2004): 25-32.