Do I need more protein if I’m a bodybuilder? Do I need less protein if I’m a marathon runner? These are valid questions about protein for athletes. Athletes participating in various activities manipulate their intakes of carbohydrates, fat, and protein differently to achieve their goals. The simple answer is that protein is key in optimizing the performance of all types of athletes and anyone who exercises, offering numerous advantages when consumed at levels above the recommended daily allowance (RDA). Some studies even show that athletes can benefit from as much as twice the RDA (1).
Athletes can be categorized into three main groups based on the goals associated with their chosen activities: endurance athletes, high-intensity athletes, and strength athletes. Endurance athletes include those who participate in activities requiring stamina, such as distance runners, swimmers, cyclists, and triathletes. High-intensity athletes compete in activities that require short, intense bursts of energy focusing on technique, lasting from seconds to only a few minutes. Such athletes include sprinters, volleyball players, and gymnasts. Like high-intensity athletes, strength athletes also engage in activities that require short bursts of energy. However, their primary goal is to attain strength and muscle mass rather than honing a sport-specific skill. The term strength athlete is synonymous with bodybuilder.
Protein has been shown to boost performance among the three categories of athletes in the following ways:
1. Endurance Athletes
Endurance athletes engage in low to medium intensity activities that elevate the heart rate for prolonged periods. To generate the energy needed to sustain low intensity exercise over a long duration, the body mainly uses the aerobic system—a system relying on the cardiovascular system to supply oxygen to the muscle. Improving endurance in athletes demands optimizing aerobic energy production, improving cardiovascular fitness, and maximizing the ability of muscle fibers to contract.
Historically, much more attention has been paid to carbohydrates in maximizing endurance than protein. “Carb-loading” is a popular dietary strategy used by endurance athletes to improve performance, and involves eating foods high in starch prior to events in an effort to maximize muscle glycogen. Glycogen is the storage form of carbohydrate that can be used by the aerobic system to supply muscles with energy. With importance placed on carbohydrate consumption in endurance activities, protein is often pushed to the wayside. Many myths regarding protein intake have circulated among endurance athletes, such as the idea that high protein intake will cause bulky muscle gains that hinder efficiency, or that high protein intake is of greater relevance to strength athletes.
However, strength and endurance athletes each have similar protein needs, with the only difference being how the body uses the protein in relation to different training regimens. While the protein consumed by strength athletes is primarily used to build muscle, it is used by endurance athletes for muscle recovery and other functions related to the effects of prolonged training. Because protein improves endurance performance in a variety of ways, false beliefs resulting in low protein intake are detrimental to the athlete.
2. High-intensity Athletes
High-intensity athletes seek to perfect technique and train their muscles to perform the powerful functional movements necessary to their sport. They engage in activity that consists of repeated bouts of short intense exercise. Such activity draws on the anaerobic system to make energy.
In contrast to the aerobic system, the anaerobic system is able to make muscle energy in the absence of oxygen. Although this system is able to rapidly produce the energy needed to drive intense bursts of activity, it cannot be relied upon for extended periods of time—less than a 2 minute maximum.
The primary goal of high-intensity athletes is to improve performance by perfecting technique and increasing speed, strength, and agility. This requires developing muscle memory for optimally performing a sport-specific movement. It also requires increasing the speed and force with which a muscle contracts, optimizing the lean muscle to fat ratio, and raising the anaerobic threshold. Supplying the body with adequate protein is essential for improving the performance of high-intensity athletes, as protein plays a key role in muscular development and fat loss, and may even beneficially influence factors that affect the anaerobic system.
Protein is the primary substrate used by muscle to achieve the optimal physical adaptations that enhance high-intensity performance. Following a strenuous workout, the body is very sensitive to the effects of protein in stimulating muscle synthesis. Eating protein during the post-exercise period promotes the synthesis of new muscle fiber proteins and an increase in contractile muscle proteins, resulting in greater strength and speed (2).
3. Strength Athletes
Strength athletes share the same goal as high-intensity athletes in improving strength, but they place a particular emphasis on aesthetics, seeking to achieve optimal muscular proportion while maximizing muscle size and definition.
Because lifting weights primes the muscles for growth, resistance training is the central component in the work-out regimen of the strength athlete. Like high-intensity athletes, strength athletes draw on the anaerobic system to get the energy they need to fuel their grueling resistance workouts. High protein intake has always been a central component of the dietary strategy used by strength athletes, as they have long recognized its value in promoting muscle synthesis.
In addition, the beneficial effects of protein in promoting fat loss and preserving muscle is extremely important to strength athletes, who desire a particularly high lean muscle to fat ratio in achieving their aesthetic goals. Although all athletes will benefit from using dietary strategies to maximize muscular development and body composition, this is particularly important to strength athletes.
Timing, Type, and Source of Protein for Any Athlete
Following intense exercise, the body is very sensitive to the effects of protein in provoking muscle synthesis. Studies suggest that there is an optimal window during which maximal benefits can be derived from eating protein. Most experts agree that protein eaten close to the end of a workout provides the greatest benefit, especially within an hour after finishing exercise. However, some benefit has even shown to be derived up to 2 hours post-exercise (1, 3).
An optimal amount of protein is needed to maximally stimulate muscle growth. Studies have shown that a dose of about 18 to 40 grams (depending on body weight, age, and workout length and type) is necessary to trigger muscle synthesis, although no greater benefit is derived from consuming amounts above this level in one sitting (2).
To optimize muscle growth and recovery throughout the day, studies suggest that several meals consisting of about 30 grams of protein each should be eaten throughout the day (3).
Whey protein, derived from milk, is superior to other protein sources for promoting muscle growth and recovery. It is absorbed faster than either casein or soy protein and is higher in BCAAs, ultimately leading to greater muscle synthesis (1, 3). In addition, its high leucine content serves as a trigger for muscle growth. Whey is also the most satiating protein, helping achieve fat loss and an improved body composition.
With the numerous advantages conferred by protein, and whey in particular, incorporating this macronutrient into a dietary and training plan will help any athlete get a leg up on the competition:
- Whey is classified as a fast-absorbing protein. It is absorbed faster to maximize peak muscle growth for high-intensity and strength athletes.
- Compared to other protein sources, whey is higher in BCAAs. BCAAs serve as a trigger for muscle growth after resistance training exercise.
- Whey protein enhances recovery after exercise because it elicits a higher insulin response that speeds up glycogen resynthesis.
- Enhanced recovery from whey protein enables greater training volume to support increased muscle growth or more frequent training.
- Whey protein stimulates greater fat oxidation following a test meal compared to other protein sources like casein or soy.
Although the goals and training techniques used to improve performance varies by athlete, protein has unanimous benefits among all athletes and exercisers of any kind and should be a central component of any good dietary strategy.
- Phillips SM, Van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci 2011;29 Suppl 1:S29-S38.
- Cribb PJ, Hayes A. Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy. Med Sci Sports Exerc 2006 Nov;38:1918-25. Doi: 10.1249/01.mss.0000233790.08788.3e
- Phillips SM, Tang JE, Moore DR. The role of milk- and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons. J Am Coll Nut. 2009 Aug;28:343-54.