Nutrition and Supplementation for Muscle Strength and Recovery
We’ve all been there—in awe at the physique of someone with huge muscles (think Dwayne “The Rock” Johnson) or astounded by a body that seems impossibly lean and toned, every muscle etched in perfect outline. While we may not be striving for this level of fitness (or able to put in the time it takes to get there!), most of us have some type of body composition goal, whether it’s simply “looking better,” attaining a specific body fat percentage, increasing muscle size and strength, or developing muscle to prevent injury. Whatever one’s fitness goal, one of the most fundamental aspects for reaching this achievement (along with regular resistance training) is nutrition, specifically the consumption of protein.
TYPES OF PROTEIN
Resistance training is the first step to muscle health, and is a topic that deserves its own separate article. The next step (which is by no means any less important!) and the one discussed herein is proper nutrition, particularly in terms of protein consumption. Proteins are large molecules composed of various combinations of twenty different molecular building blocks called amino acids. Nine of these amino acids are essential (meaning they cannot be synthesized by human cells and must be supplied from an exogenous diet), while eleven are non-essential (synthesized by the body and therefore not required in the diet); six of these twenty are further considered semi-essential, or growth-promoting, necessary to obtain from the diet in growing children and pregnant or lactating women. [1] The specific amino acid content of a food varies depending on its source (animal or plant) and the different processing/preparation the food has undergone. While it may seem trivial, the essential amino acid composition of a food has important impacts on muscle growth and recovery. For example, many people wonder if plant protein is as good as (or better than) animal protein. This question arises quite frequently, as the potential cancer-reducing/diabetes-preventing effects of a plant-based diet are widely touted. Such claims aside, the majority of studies report that good-quality (assessed by digestibility, net protein utilization, and biological value) animal proteins (such as meat, milk, and eggs) have a greater ability to enhance muscle protein synthesis rate and support muscle mass than plant-based proteins. [2] This is due to the lower digestibility of plant proteins, as well as deficiencies in certain essential amino acids such as leucine. (When an essential amino acid is not available in necessary quantities, other amino acids cannot be properly used for protein synthesis. Leucine in particular is a critical regulator of protein anabolism, or growth, stimulating protein synthesis and inhibiting protein degradation.) In support of the “superiority” of animal proteins, a meta-analyses (that is, a study of studies) looking at sixteen randomized controlled trials showed that animal-based protein had significant benefits for lean mass and several measures of leg strength (e.g. squat, knee extension, and knee flexion) compared to plant-based proteins, especially in individuals less than 50 years old. [3] All things considered, animal-based proteins hold more bang for the buck; that is, they provide a better amino acid profile and digestibility than their plant-based counterparts. Despite the physiological benefits of animal proteins, many individuals choose not to eat meat, and plant-based proteins are also more prevalent worldwide. In this regard, it is definitely still possible to consume adequate protein with a plant-based diet. So how does one obtain the necessary muscle-building amino acids from a plant-based diet? Consuming larger quantities of plant-based proteins per meal is thought to efficiently overcome their lower anabolic capacity and close the gap to the anabolic response observed with animal-based proteins. However, if one is older, consuming the necessary quantities of protein may be difficult due to typically lower appetites in older individuals. Supplementing plant proteins with branched-chain amino acids (such as the aforementioned leucine, as well as isoleucine or valine) may also increase whole-body protein synthesis by providing amino acids whose deficiency in plant proteins is usually synthesis-limiting. Mixing different plant-based proteins (such as cereals and legumes) to create a complete amino acid profile could serve as a further method to compensate for the lower anabolic capacity of these protein sources.
PROTEIN INTAKE: VOLUME
With the issue of protein quality addressed, we arrive at the question you’ve likely been wondering this whole time: How much protein do I need?? Although the specific answer to this question varies depending on body type and size, level of physical activity, total caloric intake, basal metabolism, strength goals, and other factors, the general recommendation based on scientific studies is to consume at least 1.6 grams (g) protein/kilogram (kg) body weight/day (g/kg/day) to maximize muscle protein accretion for muscle repair and strength building for individuals involved in resistance training. Individuals involved in purely endurance training require slightly less protein, about 1.2 to 1.4 g/kg/day, while training for maximal hypertrophy may require up to 2.2 g/kg/day (there are no clear muscular benefits of consuming protein in greater amounts). [4,5] 1.6 g/kg/day, and even 1.2 g/kg/day, is considerably higher than the recommended dietary allowance (RDA) for protein, currently 0.8 g/kg/day, which meets the needs of 97.5% of all healthy adult Americans not engaged in weightlifting. However, meeting the 1.6 g/kg/day recommendation typically doesn’t require special protein supplementation (via powders or bars) for most individuals who consume a varied omnivorous diet containing foods with complete amino acid profiles (meat, fish, eggs and dairy products).[6] Supplementation may be beneficial for vegetarians and vegans, or diets that are otherwise low in protein. A carbohydrate source such as glucose should also be consumed with protein, as protein synthesis cannot be modulated as effectively without the presence of insulin (which is stimulated by the intake of carbohydrates). [7]
PROTEIN INTAKE: TIMING
Considering an average protein recommendation of 1.6 g/kg/day for active, resistance-training individuals looking to build lean tissue and strength, the logical follow-up question is when this protein should be consumed, and in what quantities throughout the day. It is a commonly held belief that the timing of protein intake in the immediate pre- and post-workout period is critical for muscular adaptations. However, a meta-analysis that investigated the effects of protein timing on strength and hypertrophic adaptations following long-term resistance training protocols found no effect of timing protein intake to the immediate (within one hour) pre- and/or post-workout period on strength or hypertrophy; any hypertrophic gains observed were highly and significantly associated with the total amount of protein consumed. [8] The studies analyzed in this meta-analysis primarily consisted of non-trained individuals; in well-trained individuals, the impact of timing is less clear, with some studies showing a slight benefit of protein/creatine/glucose supplementation immediately before and after resistance exercise [9] and others showing no effect of timing on strength, power, or body-composition changes. [10] This being said, the major takeaway is that when one consumes protein is by far less important than the overall amount of protein in the diet. (For well-trained, professional athletes seeking to fully optimize their routines, consuming ~25% of daily protein immediately before or after resistance training periods may play a small role in increasing performance.)
In addition to when in relation to a resistance training session protein should be consumed, it was once thought that muscle protein synthesis was maximized with an intake of ~ 20–25 g of a high-quality protein at a single meal, and that protein excess to this at any one meal was oxidized for energy or removed as waste. However, these findings have been shown to be specific to the consumption of fast-digesting proteins; consumption of slower-acting protein sources, particularly when consumed in combination with other macronutrients, delays absorption and thus enhances the utilization of amino acids. For example, whey is a fast-acting protein with an absorption rate of ~10 g. per hour; cooked egg protein has an absorption rate of ~3 g. per hour. Thus, it may take just two hours to fully absorb 20 g. of whey protein, but about seven hours to fully absorb 20 g. of egg protein; a longer absorption time may help reduce oxidation of amino acids and promote greater whole-body protein balance. In addition, protein synthesis is not just dependent on the amount of protein in a meal, but the difficulty of a previous workout, stress hormones and other chemical messengers, current fitness level, and numerous other factors. Rather than focusing on a protein “ceiling” for a single meal, a better strategy is to focus on consuming the amount of protein at each meal that allows one to obtain enough total protein throughout the day. If one is looking for a good rule of thumb, data suggests consuming protein at a target intake of 0.4 g/kg/meal across a minimum of four meals in order to reach a minimum of 1.6 g/kg/day. Using the upper daily intake of 2.2 g/kg/day spread out over the same four meals would necessitate a maximum of 0.55 g/kg/meal. [11] For an average 120 lb. female athlete, consumption of 87 grams of protein per day, spread out across three or four meals of 29 to 22 grams protein each, respectively, is ideal. For an average 160 lb. male, the recommendation would be 116 grams of protein per day, consumed in three or four allotments of 39 to 29 grams protein per meal, respectively.
CONCLUSION
As we have seen, achieving desired body composition goals involves a multifaceted approach that incorporates both regular resistance training and proper nutrition. While resistance training is essential for building muscle mass and strength, adequate protein consumption is equally crucial for optimizing muscle growth, recovery, and overall health. The quantity of protein consumed is the most important factor for reaching body composition, strength, or performance goals; protein quality and timing can be adjusted as needed for your own specific situation. By understanding the role of protein in muscle synthesis and health, and by incorporating protein into a balanced diet, individuals can effectively support their fitness goals and enhance their overall well-being.
TLDR;
Animal-based protein sources have a more complete amino acid profile and better digestibility than plant-based protein sources, allowing for higher rates of protein synthesis. If you are an individual who eats both animal and plant foods, animal proteins are the better option for strength and recovery. However, one can absolutely still consume a plant-based diet that is high in protein and more than adequate for protein synthesis and muscle health/development. Eating more protein, mixing different plant protein sources, or supplementing with branched chain amino acids will help provide an extra boost for plant-based diets. In general, eating about 1.6 g/kg/day of protein is ideal for increasing strength, repairing tissue, maintaining/increasing muscle mass when consumed in combination with a regular resistance training program.
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