When it comes to performance nutrition for endurance athletes, carbs are king, but runners who also consider their protein requirements during and after training and racing can achieve even better results.
A high-carbohydrate, low-protein diet, which is common among recreational runners, can lead to fatigue and increased protein turnover (the rate at which muscle proteins are broken down and converted into energy).
Without the correct nutritional approach, this combination of factors can compromise performance and recovery, especially when we engage in high-volume or high-intensity training.
Running damage
The most important role that protein plays is supporting recovery and tissue repair after hard or prolonged efforts.
When we run, the repetitive impact and forceful contractions cause microscopic tears in the muscle fibres.
The metabolic reactions that occur inside muscle cells to produce energy (this happens in structures called mitochondria) can also result in cellular damage and inflammation.
Post-exercise recovery
After exercise, your muscles are more receptive to nutrients, including the amino acids we get from protein, which are vital for rebuilding and strengthening damaged muscle tissue.
Protein intake, especially within the first hour or two after a run stimulates muscle protein synthesis (MPS) – the process of building new muscle proteins. This helps repair the damaged tissue and supports the adaptations that happen in response to training that make muscles stronger over time.
Protein also supports hormone production and immune system function, which are other critical factors in the recovery process.
Due to the important role protein plays in the recovery process, runners must include this macronutrient in their post-exercise nutrition plan, alongside quality carbohydrates to replenish glycogen stores.
The best approach is to meet your daily recommended protein requirements by including natural animal and plant-based protein sources in every meal.
The recommended intake for athletes and active individuals is at least 1.6g/kg/day. For a 55kg female runner, that equates to 88g a day (this is derived protein, not the total weight of the protein you eat), and 120g for a 70kg male runner, as examples.
Derived protein explained: If you eat 100g of chicken, the derived protein from that chicken might be around 25-30g because chicken is not 100% protein.
Post-workout protein supplements
A quality protein supplement offers a convenient and effective source of protein soon after a training session or race, which offers an ideal approach to meet your immediate muscle repair and recovery needs as a whole food meal might not be available, or well tolerated so soon after a hard effort.
Due to the convenience and bioavailability (how quickly your body can digest and absorb protein), a recovery supplement that includes protein provides a readily available pool of amino acids to help mend the micro-tears that occurred during your run.
When it comes to optimising recovery, whey protein is widely considered the gold standard due to its superior bioavailability. Whey also boasts a complete amino acid profile, containing all the essential amino acids (EAA) your body needs but cannot produce, including the branched-chain amino acids (BCAA) leucine, isoleucine and valine, which play a vital role in tissue repair.
Plant-based protein supplements also offer athletes – not just vegans or vegetarians – an effective option, with added potential benefits for post-exercise recovery, such as less potential impact on inflammation (animal-derived proteins can increase inflammation) and less risk of negative reactions among athletes with a lactose intolerance or allergy, or dairy-based gastrointestinal (GI) issues.
Protein during running
Protein can also have a positive impact on endurance performance when athletes run for three hours or more, like during ultra-endurance events like the iconic Comrades or Two Oceans ultra-marathons or while training for these races.
Taking in protein or amino acids from a drink or solid food source during training and racing mainly benefits performance and recovery by limiting muscle tissue damage.
While studies show that the body can break down ingested or muscle protein for energy during running, particularly when your carb intake is sub-optimal (this happens via a process known as gluconeogenesis, or GNG), we can only meet approximately 5-10% of our total energy requirements from protein over a very prolonged event.
The more important and relevant benefit, particularly for runners preparing for or competing in an ultra-endurance event, is the positive benefits that a carbohydrate-protein drink can have on reducing the amount of muscle damage that happens while you are running.
First and foremost, a carb-protein supplement taken during ultra-endurance running events can delay the onset of fatigue from the cumulative muscle damage that occurs during the hours and hours spent running.
During a race, even a small amount of protein can provide the building blocks needed to begin the muscle repair and remodelling processes, which can help mitigate the extent of damage that occurs.
Research backs up this claim, with a study done at the Institute of Human Physiology in Verona, Italy, finding that conditioned athletes who were trekking through a mountainous area, at an average altitude of 10,000 feet, for 21 days lost no muscle mass when taking a BCAA supplement – in fact, they gained muscle.
This finding was in stark contrast to the norm, where athletes normally lose significant body mass, particularly from muscle, due to the extreme physical exertion and hypoxia (lack of oxygen). This suggests that protein’s ultimate benefit in a carb-protein supplement is its muscle-sparing effect.
When it comes to training, by limiting muscle damage, protein can reduce both the inflammatory response and delayed onset muscle soreness (DOMS), which can have a positive, albeit indirect effect on performance as better recovery between sessions lets you engage in consecutive days of hard training and back-to-back long runs.