Protein is an essential macronutrient for endurance athletes, playing a key role in muscle repair, growth, and overall recovery. While whole foods should always be the foundation of any diet, protein supplements for athletes are a convenient way to meet increased protein needs, especially when time is limited. In this blog post, I’ll explore what protein is, how much athletes need, different types of protein supplements, when to take them, and potential side effects to watch out for.
What Is Protein?
Proteins are made up of amino acids, think of these as the building blocks to support muscle repair, growth, and recovery, leading to improved performance and increased muscle mass. There are a total of 20 amino acids, 9 of them are essential and 11 of them are nonessential. Essential amino acids must be obtained from food because the body cannot produce them. A complete protein contains all nine essential amino acids in adequate amounts. Animal-based protein sources such as dairy are complete proteins because they contain all nine essential amino acids. Soy is an example of complete plant-based protein.
Incomplete proteins lack sufficient amounts of one or more essential amino acids. Many plant-based proteins fall into this category. However, athletes can get all the essential amino acids by mixing different plant proteins, like rice and pea protein.
Protein’s Role in Muscle Repair, Growth, and Health
For athletes, protein plays a vital role in muscle protein synthesis, the process where muscles repair and grow after exercise. Resistance training and endurance workouts break down muscle proteins, which must be replenished with dietary protein to support recovery.
In addition to muscle repair, protein is crucial for:
- Maintaining muscle mass during periods of intense training or calorie deficits
- Supporting immune function, as antibodies and immune cells rely on protein
- Enhancing recovery, allowing athletes to train consistently with less risk of injury
How Much Protein Do Athletes Need?
The general recommendation for protein intake in healthy adults is 0.8 grams per kilogram (g/kg) of body weight per day. However, athletes require more protein to meet their training demands, typically between 1.2 to 2.0 g/kg/day.
Consuming ~20–40 grams of protein per meal spread evenly throughout the day is the most effective strategy for muscle growth. Eating protein every 3–4 hours maximizes muscle protein synthesis while preventing excessive breakdown.
It is a common myth that eating extra protein beyond this range leads to more muscle growth. The body will simply use excess amino acids for energy or store them as fat. Instead of overloading on protein at one meal, athletes should distribute their intake throughout the day.
Why Athletes Use Protein Supplements
Protein supplements can be beneficial for:
- Convenience: Busy schedules may make it difficult to prepare high-protein meals, and supplements offer a quick alternative.
- Post-workout recovery: Choosing a liquid form of protein (protein shake) over a solid may help athletes consume their recovery nutrients shortly following exercise.
- Meeting higher protein needs: Some athletes struggle to get enough protein from food alone, making supplementation a helpful tool.
Types of Protein Supplements for Athletes and How to Choose the Right One
There are various types of protein supplements available, each with different benefits depending on dietary preferences and goals.
1. Whey Protein
Whey is a fast-digesting, high-quality protein derived from milk. It is rich in all essential amino acids and contains a high amount of leucine. A post-training supplement should contain at least 3g of leucine per serving to support optimal muscle growth and recovery.
- Whey protein concentrate: 35–80% protein, contains some lactose and fat.
- Whey protein isolate: 90–96% protein, lower in lactose and fat.
- Whey protein hydrolysate: Pre-digested for faster absorption
Who is it good for?
- Individuals who tolerate dairy well
- Strength and endurance athletes who need fast muscle recovery
- Those looking for a high quality, easily digestible protein
2. Casein Protein
Casein is the other major protein found in milk but digests much slower than whey. It provides a steady release of amino acids, making it ideal for overnight muscle recovery.
Who is it good for?
- Athlete’s needing sustained protein release
- Those looking to prevent muscle breakdown during longer periods without food
3. Soy Protein
Soy protein comes from soybeans and is a complete plant-based protein. It is highly digestible, making it easy for the body to absorb.
Who is it good for?
- Vegans and vegetarians
- Individuals with dairy allergies
- Athletes looking for a complete plant-based protein
4. Pea Protein
Pea protein is extracted from yellow peas and is highly digestible. It is not a complete protein because it is low in methionine. It is best used in combination with another protein source.
Who is it good for?
- Vegans and vegetarians
- Individuals with soy or dairy allergies
- Those looking for an easily digestible plant-based protein
5. Brown Rice Protein
Brown rice protein is extracted from brown rice and is a plant-based option that is easy to digest. It is not a complete protein because it is low in lysine so it’s often combined with pea protein to improve its amino acid profile.
Who is it good for?
- Vegans and vegetarians
- Those with dairy or soy allergies
- Budget-conscious athletes looking for an affordable plant-based option
6. Hemp Protein
Hemp protein comes from hemp seeds and is less processed than soy or pea protein. It has a similar amino acid profile to soy but is lower in lysine. While it provides less protein per serving, it offers added benefits like fiber and healthy fats.
Who is it good for?
- Vegans and vegetarians
- Athletes who prefer less processed protein sources
- Those looking for additional fiber in their diet
When to Take Protein
Before and During Training
- Small amounts of protein before a workout may support muscle growth, but research is mixed on whether protein during exercise enhances endurance performance.
After Training for Recovery
- Consuming 20–40 grams of protein post-workout helps maximize muscle recovery.
- There is no exact time window for when protein should be consumed after a training session but eating protein soon after exercise is beneficial.
- An optimal post-training supplement should include a minimum of 3 g of leucine per serving. When choosing plant-based proteins, be sure to check the label to ensure it meets this requirement.
Throughout the Day
- Aim for protein every 3–4 hours to optimize muscle protein synthesis.
How to Take Protein Supplements
Protein powders can be incorporated into a variety of meals and snacks, including:
- Mixed with water or milk
- Stirred into oatmeal or yogurt
- Added to smoothies
- Used in baking (muffins, pancakes, waffles, energy balls)
Potential Side Effects of Protein Supplements
While protein supplements can be beneficial, there are potential downsides:
1. Digestive Issues
- Lactose intolerance: Whey and casein protein contain lactose, which may cause bloating or discomfort. Whey isolate or plant-based proteins may be better alternatives.
- Artificial Sweeteners: Some protein powders contain artificial sweeteners that can cause G.I. upset.
- Fillers: These increase the volume of protein powder but may cause bloating or gas.
2. Nutrient Imbalance
- Relying too much on protein supplements can lead to deficiencies in vitamins, minerals, and fiber from whole foods.
Supplement Safety
Supplements aren’t tightly regulated by the government, which means they may not go through strict safety testing before being sold. As a result, some products contain harmful or banned substances due to contamination or poor manufacturing practices, even if they aren’t listed on the label.
A nonprofit organization, the Clean Label Project, published a report on toxins found in protein powders. Researchers tested 134 products for 130 different toxins and discovered that many protein powders contain heavy metals, BPA (a chemical used in plastic production), pesticides, and other contaminants linked to various health issues. One protein powder contained 25 times the allowable limit of BPA.
It can be challenging for consumers to identify trustworthy manufacturers. The NSF Certified for Sport label ensures that supplements are free from unsafe levels of contaminants, prohibited substances, and masking agents, while also ensuring that the ingredients listed on the label match those in the product.
Final Thoughts: Protein Supplements for Athletes
Protein supplements for athletes can be a valuable tool to support muscle recovery, improve performance, and meet higher protein needs. However, choosing the right protein depends on dietary preferences, goals, and allergies or intolerances. By incorporating a variety of protein sources and balancing whole foods with supplements, athletes can optimize their performance and recovery effectively.
For personalized nutrition support, connect with Stephanie for 1-on-1 coaching tailored to your specific nutrition goals!
References
Clean Label Project. (n.d.). The best & worst protein powder products. https://cleanlabelproject.org/the-best-worst-protein-powder-products/
Gatorade Sports Science Institute. (n.d.). The science of protein. https://performancepartner.gatorade.com/content/resources/pdfs/science-of-protein-2024.pdf
Harvard Health Publishing. (2022). The hidden dangers of protein powders. https://www.health.harvard.edu/staying-healthy/the-hidden-dangers-of-protein-powders
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NSF Certified for Sport. (n.d.). What our mark means. https://www.nsfsport.com/our-mark.php
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