Protein power: what cyclists need to know about protein!

Nutritionist Corinne Reinhard provides answers to the most important questions on the topic of “proteins in cycling”. Learn from the nutrition expert about the right timing for protein intake, the optimal amount and different types of protein sources.

Corinne Reinhard holds a postgraduate diploma in sports nutrition from the International Olympic Committee and has more than ten years of experience in nutrition counselling and nutrition coaching for athletes.

Why is protein so important for endurance athletes?

Protein has numerous functions in our body. It is an important nutrient that supports our health, including a stable immune system, and physical performance. Adequate protein intake is therefore an important piece of the puzzle for optimal training adaptations and performance in sport.

For cyclists, protein is a key factor especially during recovery. Protein intake prevents muscles from a catabolic state and promotes muscle repair and building. Over time, this can support muscle strength and optimal body composition.

Do endurance athletes have an increased “protein requirement”?

Endurance athletes need more protein than inactive people. This is because endurance training puts stress on muscle and tendon tissue. In order to repair and maintain integrity and function of their protein structures, an adequate intake of dietary proteins is required.

This is because proteins from food ultimately provide the essential (indispensable) amino acid building blocks needed for this purpose.

Furthermore, depending on duration and intensity of exercise, the body may break down muscle and body proteins into their amino acid building blocks and use them as an energy source.

The body’s own proteins can thus be used to varying degrees as an energy source under stress and must in turn be replaced by taking in dietary proteins; especially essential amino acids that our body cannot produce itself. All these factors can contribute to an increased protein requirement in endurance athletes.

How many grams of protein should a cyclist consume per day?

As with most dietary principles, protein requirements vary from athlete to athlete. There is no one-size-fits-all recommendation. Many different factors, such as type of diet, training volume and athletic goal, determine the individual protein requirement – which can also change depending on the training periodisation.

Leading scientists in this field recommend a daily protein intake of about 1.6 to 1.8 grams per kilogram of body weight for adults who train between 1 and 3 hours per day. Most endurance athletes who consume enough energy to cover their requirements for training and performance will easily take in this amount with their food.

Road cyclists with very high training volumes and/or those who want to optimise body composition by means of an energy-reduced diet, may benefit from a daily protein intake of up to 2.4 grams of protein per kilogram of body weight.

Do women have different protein requirements than men?

The most common and also most practical recommendation for protein intake relates to body weight. Since women are generally lighter than men, their absolute amount of protein per day is lower.

Currently, the same recommendations for protein intake per kilogram of body weight apply to both women and men, as mentioned above. However, women are often underrepresented in studies, so there is certainly still a lot of research to be done.

However, some study results suggest that protein requirements may not always be the same during the different phases of the menstrual cycle.

How many times a day should protein be consumed via food?

Ideally, the total amount of daily protein should be consumed evenly distributed over 4 (to 5) meals at regular intervals (for example every 4 hours) throughout the day. This means to take in an amount of 0.3 to 0.4 (0.5) grams of protein per kilogram of body weight at breakfast, lunch, as a post-workout snack and at dinner – plus an additional snack before bed if needed.

At least theoretically. Experience shows that athletes rarely watch their protein intake as closely in their daily lives – and this is certainly not always necessary, either. However, athletes should at least roughly know how much protein they consume. Therefore, athletes need to know how much protein various foods contain. They should also make sure to evenly distribute the optimal amount of protein throughout the day, as breakfast in particular often does not contain the recommended amount of protein.

Example calculation for the daily protein requirement of a hobby cyclist:

Fictitious example for a 75 kg cyclist with a requirement of 1.8 grams of protein per kilogram of body weight:
Results in 135 grams of protein per day and could be distributed, for example, as follows to always achieve 0.3-0.4 grams of protein per kilogram of body weight per meal/snack
Breakfast: approx. 30 grams of protein
Lunch: approx. 40 grams of protein
Post-training snack: approx. 25 grams of protein
Dinner: approx. 40 grams of protein

Does it make sense to consume protein directly after exercise?

One pragmatic piece of advice is certainly to incorporate some form of post-workout nutrition after long or intense endurance sessions rather than eat nothing at all. However, the importance of immediate protein intake within minutes after you’ve finished your exercise is somewhat exaggerated. Post-workout recovery and adaptation processes take longer than just the – bluntly said – often proclaimed 29 minutes and 59 seconds. It is rather key to take in proteins regularly and distribute them well throughout the day.

What is the most important amino acid for endurance athletes?

A sufficient intake of all nine essential amino acids is crucial for general health, the immune system and in terms of optimal muscle supply. This is because the body cannot produce any of these essential amino acids itself, which are isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine and histidine. Leucine has a special function.

This essential amino acid is not only a building block for the muscles, but also activates muscle repair and muscle building processes, i.e., it is the strongest trigger for muscle protein synthesis. Milk protein, for example, and especially whey protein, are particularly rich in essential amino acids, including a high leucine content. But there are many other good sources of protein, too.

Animal products such as eggs, dairy products and meat contain high-quality proteins. What options do vegetarians and vegans have to get enough high-quality protein?

Vegetable protein in legumes, nuts, seeds, cereals and potatoes has, on average, a lower total content of essential amino acids – especially leucine – compared to animal protein. Corn protein is exceptionally rich in leucine but low in other essential amino acids.

In any case, it is advisable to eat varied, just like in any healthy diet. Different vegetable protein sources can be combined in meals to ensure optimal amounts of all nine essential amino acids.

If you eat purely plant-based, however, the total protein intake should be kept in mind first and foremost, as it is often somewhat easier to cover increased protein requirements with animal protein sources such as dairy products, eggs, fish and meat. But, of course, it is also possible for vegans to supply their body and muscles with sufficient protein.

How can protein help with weight loss?

The goal of weight loss is usually to reduce body fat while maintaining valuable muscle mass. Higher protein intake during a calorie-restricted diet can contribute to increase body fat loss and prevent the loss of lean body mass, including muscle, at the same time – for many reasons: If, e.g., the body suffers a calorie deficit, higher protein intake is necessary to avoid a negative muscle-protein balance and thus prevent muscle loss.

Furthermore, metabolising and digesting dietary proteins is complex and requires significantly more energy compared to carbohydrates and fats. The so-called thermogenic effect, also called food-induced thermogenesis, is therefore higher. Moreover, no nutrient is more filling than protein: fat and carbohydrates sate less effectively.

Does protein intake make sense during endurance training or a competition?

There is no evidence that protein intake during endurance exercise in combination with carbohydrates further improves performance compared to adequate carbohydrate intake.

However, protein intake during prolonged endurance exercise can help replace amino acids in the body that have been used as an energy source. This allows the muscular recovery process to begin more quickly after exercise.

It is therefore possible that protein intake during very long-duration exercise, such as ultramarathons, could be helpful in combination with low glycogen storage availability. During such exercise, protein can account for a total of 5 to 10 per cent of the total energy supply.

However, whether protein is well tolerated during exercise, i.e., does not lead to gastrointestinal problems must always be tested individually.