Protein and Performance

What is a sensible amount and when does more protein become unnecessary? Protein isn't "quick fuel" like carbohydrates, but it does affect how well you recover and the sustainability of your training over time. This article explains how much protein is reasonable for endurance athletes, how to get the most benefit by spreading intake smartly throughout the day, and when timing after workouts actually matters. Many feel better with a slightly higher intake than old minimal recommendations, especially during volume periods, but the effect is as much about the overall picture and distribution as it is about maximizing grams in a single shake.

Among our three macronutrients (excluding alcohol) – carbohydrates, fats, and protein – we've only briefly touched on protein in the articles about Optimal Recovery and the two-part series on Weight Loss. Protein doesn't provide an immediate performance boost like carbohydrates can, but for many athletes, it's an essential part of their diet. Now, we're revisiting our protein knowledge.

How much protein is the “right” amount? What do the recommendations look like for us endurance athletes who want to perform?

And yes – the picture might have been a bit misleading, but it's perfectly fine to use protein powder in cooking as well 😉

The recommended protein intake for athletes is 1.2-1.4 g/kg of body weight per day. This can be compared to the reference intake for the general population, which is 0.8 g/kg of body weight per day. For athletes, the protein need is generally 50-75% higher than for non-active individuals.

Larger studies on endurance athletes show that about 80% reach the lower limit of 1.2 g/kg of body weight per day (source). In these studies, 24-hour food questionnaires are often used where participants fill in what they have eaten over the last day. Such forms (Food Frequency Questionnaire – FFQ) are easy for study participants to use, but we often forget parts of what we've eaten. Elite athletes are usually better at keeping track, but self-reporting always has a certain margin of error. Try to remember everything you consumed yesterday and approximately how much of each thing – it's harder than you think.

The research trend is leaning towards suggesting that a somewhat higher intake might be better for active individuals. As early as 2009, an intake of 1.2–1.7 g/kg of body weight per day was suggested. A common tool for calculating protein needs is measuring nitrogen in urine, as protein contains nitrogen. However, this method has limitations: with increased protein intake, we excrete more nitrogen and conserve nitrogen with lower intake. The body thus regulates nitrogen balance.

A newer study from 2016 using more reliable measurement methods found a requirement for endurance athletes of 1.53–1.83 g/kg of body weight per day (depending on the measurement method). The authors therefore recommended a higher intake than the traditional 1.2–1.4 g/kg. The study involved runners with a weekly volume of 45-130 km/week (4.5-13 miles/week) who, over three days, ran a total of 35 km distributed over 10, 5, and 20 km at self-chosen pace.

The trend is clear: during volume weeks, your protein needs increase in accordance with your higher energy and carbohydrate demands if you want to recover effectively. Feel free to periodize your protein intake and use a recovery drink when you need to accelerate recovery.

Many studies on protein focus on strength sports (anaerobic activities), which are not as energy-demanding as endurance sports. Endurance athletes often have a higher energy intake, which also means we often consume more protein "automatically." Many carbohydrate sources also have a significant amount of protein. For example, dry pasta contains 12–14% protein.

An important aspect is not just the total amount of protein, but also how it's distributed throughout the day. Muscle protein synthesis (MPS) is the process that builds new muscle protein. It has been shown that protein pulses where each intake contains about 20 g of complete protein provide a stronger signal for muscle building than lower intakes. Comparisons post-workout indicate that 40 g of protein does not stimulate MPS more than about 20–30 g for most individuals (source).

Practically, this means if you distribute your protein intake to 3–4 occasions per day where each meal contains at least 20 g of complete protein, you'll get a stronger stimulus for muscle building compared to snacking on protein all day long. It seems that amino acid levels need to drop to baseline before a new peak of amino acids provides a building signal. Sudden increases of amino acids (3–5 times per day) — as part of a total daily intake of about 1.8–2.0 g/kg body weight — are likely more beneficial than constantly elevated levels.

If you weigh 70 kg, 1.8–2.0 g/kg corresponds to approximately 126–140 g of protein per day. Distributed over four intakes, each meal should then provide about 30–35 g of complete protein. Complete protein contains all essential amino acids and can be found in many animal sources like meat, milk, and eggs. There are also plant-based complete sources like quinoa, soybeans, tofu, and buckwheat, or through combinations such as grains + legumes (for instance, rice + peas in a risotto). There are also plant-based protein powders/recovery drinks that combine, for example, soy + pea protein or oats + pea protein, creating a protein powder that can be equally complete and optimal as whey.

There is always an upper limit where intake beyond that threshold begins to have negative effects, regardless of what we consume. Regarding protein, myths have circulated that high intake can lead to impaired kidney function and decreased bone density. A study (No. 79) indicated an increased risk of osteoporosis with higher protein intake, but the majority of studies (e.g., 80, 81) indicate quite the opposite.

There are also communities in Northern Canada/Alaska where protein can make up 34% of energy intake over a long period. In practice, this is around 3 g of protein/kg body weight/day, which is nearly four times our recommended intake. Therefore, we can't establish a clear "dangerous" upper limit based on current data, and longitudinal studies are lacking.

Based on what we know today, we would say that intake of 2–2.5 g/kg per day is probably okay. Intake over 2.5 g/kg is likely unnecessary for most endurance athletes. From an environmental perspective, the planet would benefit if we reduced our animal-based protein intake or based it more on plant sources, but that will be a subject for another article in the future.

Let's clear up this myth immediately – consuming more than 20g of protein per meal does not mean you simply pee out the excess protein. As mentioned earlier, around 20g of protein is typically sufficient to signal your body to start rebuilding and repairing. However, this doesn't mean that additional protein is unnecessary. Extra protein contributes to your total daily intake and, combined with carbohydrates, assists your body in reducing muscle breakdown.

Muscle building and muscle breakdown are continuously occurring simultaneously. The objective is to ensure that building surpasses breakdown. A high temporary protein intake aids in stimulating building, while protein + carbohydrates help slow down breakdown.

Short answer: no, skip it (in most cases). Studies with carbohydrates + protein during exercise show that protein does not provide additional performance enhancement—it's the carbohydrates that are "the boss" when it comes to energy supply in endurance sports (source).

Even during strength training, there's no significant advantage to consuming protein or amino acids during the session itself, at least not for directly stimulating muscle protein synthesis. The training itself already upregulates MPS; the body can't optimally break down and build up at the same time—it's like having too many cooks in the kitchen.

However, you can consume EAA or BCAA during activity for other reasons. There is a hypothesis that they may affect mental fatigue, but for muscle building, it doesn't help during the workout itself. For further reading, Asker Jeukendrup's article on protein intake for endurance athletes is recommended, with reference and additional sources.

In 2014, two systematic reviews were published by the same research group. One reviewed the literature on protein supplements and their effect on muscle breakdown, muscle fatigue, recovery, muscle function, and physical performance. Half a year later, another focused on the effect on muscle mass, strength, and aerobic and anaerobic power development. Both are interesting, but here we focus on the first, which looks at recovery and performance.

The main conclusion is that if you already consume a substantial meal right after training, meaning you take in at least 20 g of high-quality protein within a short period, extra protein supplements immediately after the session don't provide a significantly greater effect on recovery. However, the studies vary in protocols and do not always control energy intake (isocaloric design is sometimes lacking), which affects interpretation.

The greatest effect of specific recovery drinks (recovery, gainer, etc.) is seen if you are in a calorie deficit or have a low protein intake otherwise. Fewer biomarkers for muscle damage and less soreness are observed when a recovery drink with at least 20 g of high-quality protein is consumed immediately after daily training. If, instead, you train 1–2 times a week and eat food shortly after the sessions (with at least 20 g of high-quality protein), an extra recovery drink does not significantly improve over time. Yet, during periods of high training volume or daily sessions, a recovery drink can speed up recovery so you perform better the next day—or at least don't have as much muscle soreness.