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The Smartest Way To Use Protein To Build Muscle (Science Explained)Protein intake for athletes -
The same goes for protein. It sounds like a lot—yes, but the good news is that there are a wide array of foods that are high in protein and taste great, too.
Of course, you do not need to get all of your protein from any one source at each meal or snack, so feel free to mix and match the above as you move and eat throughout your day. There are a few other important considerations when speaking about adequate protein intake. One is that in order for your resistance training and protein eating to pay off in terms of muscle and strength gains, you need to be taking in adequate energy calories each day.
So take care to fuel your body and your workouts adequately as you also pay attention to adequate protein intake.
If you happen to be in an overall calorie deficit and also want to maintain muscle during that period, you will want to increase your protein intake to closer to 2. Another consideration for sufficient protein intake is that, as we age, absolute protein needs have been shown to increase , thus the above protein goal and numbers may fall a bit short for older athletes.
Research is currently ongoing on this important topic, but we do know that Masters athletes looking to maintain or gain lean body mass may need to ingest closer to 30 or even 40 grams of protein four times daily , as protein utilization rates decrease with age thus we need to eat more absolute grams of protein to meet daily repair and recovery needs.
We always recommend a food-first approach, since foods contain many beneficial nutrients and compounds in addition to protein. But many busy athletes find it tricky to consistently take in adequate protein four times per day and may benefit from adding a supplement from time to time, or even once per day.
If you do supplement your diet with protein shakes, powder, and drinks , remember that they are not regulated, which means they might include not-so-good-for-you ingredients that are not listed on the label. There are many options to choose from, and luckily, you can choose whether you would like to include a milk-based whey or casein or plant-based generally from pea, hemp, soy, or a combination of the three based on your personal preference.
Regarding protein type, while you may have heard that including specific amino acids, mainly branched-chain amino acids BCAAs and specifically Leucine , is needed in order to stimulate maximum muscle protein synthesis, the most recent research concludes that as long as you are taking in at least 20 to 30 grams of protein post-workout and at each meal with one snack to total four times per day, you do not need to focus specifically on BCAAs.
Still, both milk-based proteins whey and casein are touted as being high in BCAAs and demonstrate high nitrogen retention and bioavailability meaning a higher percentage of the total protein you eat will be put to good use in studies on protein supplementation in resistance-training athletes.
For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1. Recommendations regarding the optimal protein intake per serving for athletes to maximize MPS are mixed and are dependent upon age and recent resistance exercise stimuli.
General recommendations are 0. The optimal time period during which to ingest protein is likely a matter of individual tolerance, since benefits are derived from pre- or post-workout ingestion; however, the anabolic effect of exercise is long-lasting at least 24 h , but likely diminishes with increasing time post-exercise.
While it is possible for physically active individuals to obtain their daily protein requirements through the consumption of whole foods, supplementation is a practical way of ensuring intake of adequate protein quality and quantity, while minimizing caloric intake, particularly for athletes who typically complete high volumes of training.
Rapidly digested proteins that contain high proportions of essential amino acids EAAs and adequate leucine, are most effective in stimulating MPS.
Different types and quality of protein can affect amino acid bioavailability following protein supplementation. Athletes should consider focusing on whole food sources of protein that contain all of the EAAs i.
Endurance athletes should focus on achieving adequate carbohydrate intake to promote optimal performance; the addition of protein may help to offset muscle damage and promote recovery.
Pre-sleep casein protein intake 30—40 g provides increases in overnight MPS and metabolic rate without influencing lipolysis. In , the International Society of Sports Nutrition ISSN published its first position stand devoted to the science and application of dietary protein intake [ 1 ].
Subsequently, this paper has been accessed more than , times and continues to serve as a key reference on the topic. In the past ten years, there have been continued efforts to advance the science and application of dietary protein intake for the benefit of athletes and fitness-minded individuals.
This updated position stand includes new information and addresses the most important dietary protein categories that affect physically active individuals across domains such as exercise performance, body composition, protein timing, recommended intakes, protein sources and quality, and the preparation methods of various proteins.
Most of the scientific research investigating the effects of protein intake on exercise performance has focused on supplemental protein intake. From a broad perspective, the dependent measures of these studies can be categorized into two domains:.
Very few studies have investigated the effects of prolonged periods one week or more of dietary protein manipulation on endurance performance. The trained cyclists ingested each diet for a 7-day period in a randomized, crossover fashion. Before and following the 7-day diet intervention, a self-paced cycling endurance time trial was conducted as the primary measure of exercise performance.
It should be noted however that a 7-day treatment period is exceedingly brief. It is unknown what the effect of a higher protein diet would be over the course of several weeks or months. Although the number of investigations is limited, it appears as if increasing protein intakes above recommended intakes does not enhance endurance performance [ 2 , 4 , 5 ].
In addition to these studies that spanned one to three weeks, several acute-response single feeding and exercise sessions studies exist, during which protein was added to a carbohydrate beverage prior to or during endurance exercise.
Similarly, most of these interventions also reported no added improvements in endurance performance when protein was added to a carbohydrate beverage as compared to carbohydrate alone [ 6 , 7 , 8 , 9 ].
An important research design note, however, is that those studies which reported improvements in endurance performance when protein was added to a carbohydrate beverage before and during exercise all used a time-to-exhaustion test [ 10 , 11 , 12 ].
When specifically interested in performance outcomes, a time trial is preferred as it better mimics competition and pacing demands. In conclusion, added protein does not appear to improve endurance performance when given for several days, weeks, or immediately prior to and during endurance exercise.
For these reasons, it seems prudent to recommend for endurance athletes to ingest approximately 0. Another important consideration relates to the impact of ingesting protein along with carbohydrate on rates of protein synthesis and balance during prolonged bouts of endurance exercise.
Beelen and colleagues [ 14 ] determined that adding protein to carbohydrate consumption throughout a prolonged bout of endurance exercise promotes a higher whole body net protein balance, but the added protein does not exert any further impact on rates of MPS.
While performance outcomes were not measured, these results shift the focus of nutrient ingestion during prolonged bouts of endurance exercise to the ingestion of carbohydrate. When adequate carbohydrate is delivered, adding protein to carbohydrate does not appear to improve endurance performance over the course of a few days or weeks.
Adding protein during or after an intensive bout of endurance exercise may suppress the rise in plasma proteins linked to myofibrillar damage and reduce feelings of muscle soreness.
There are relatively few investigations on the effects of protein supplementation on endurance performance. The extent to which protein supplementation, in conjunction with resistance training, enhances maximal strength is contingent upon many factors, including:.
Co-ingestion of additional dietary ingredients that may favorably impact strength e. creatine, HMB. Taking each of these variables into consideration, the effects of supplemental protein consumption has on maximal strength enhancement are varied, with a majority of the investigations reporting no benefit [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ] and a few reporting improvements in maximal strength [ 26 , 27 , 28 , 29 ].
With limited exceptions [ 16 , 18 , 23 , 27 ], most of the studies utilized young, healthy, untrained males as participants. In one investigation examining college football athletes supplementing with a proprietary milk protein supplement two servings of 42 g per day for 12 weeks, a These differences were statistically significant.
When females were the only sex investigated, the outcomes consistently indicated that supplemental protein does not appear to enhance maximal strength at magnitudes that reach statistical significance.
Hida et al. An important note for this study is that 15 g of egg protein is considered by many to be a sub-optimal dose [ 31 ]. However, others have advocated that the total daily intake of protein might be as important or more important [ 32 ].
In another study, Josse et al. In summary, while research investigating the addition of supplemental protein to a diet with adequate energy and nutrient intakes is inconclusive in regards to stimulating strength gains in conjunction with a resistance-training program to a statistically significant degree, greater protein intakes that are achieved from both dietary and supplemental sources do appear to have some advantage.
Hoffman and colleagues [ 29 ] reported that in athletes consuming daily protein intakes above 2. Cermak and colleagues [ 35 ] pooled the outcomes from 22 separate clinical trials to yield subjects in their statistical analysis and found that protein supplementation with resistance training resulted in a A similar conclusion was also drawn by Pasiakos et al.
Results from many single investigations indicate that in both men and women protein supplementation exerts a small to modest impact on strength development.
Pooled results of multiple studies using meta-analytic and other systematic approaches consistently indicate that protein supplementation 15 to 25 g over 4 to 21 weeks exerts a positive impact on performance.
Andersen et al. When the blend of milk proteins was provided, significantly greater increases in fat-free mass, muscle cross-sectional area in both the Type I and Type II muscle fibers occurred when compared to changes seen with carbohydrate consumption.
Collectively, a meta-analysis by Cermak and colleagues [ 35 ] reported a mean increase in fat-free mass of 0.
Other reviews by Tipton, Phillips and Pasiakos, respectively, [ 36 , 38 , 39 ] provide further support that protein supplementation 15—25 g over 4—14 weeks augments lean mass accretion when combined with completion of a resistance training program. Beyond accretion of fat-free mass, increasing daily protein intake through a combination of food and supplementation to levels above the recommended daily allowance RDA RDA 0.
The majority of this work has been conducted using overweight and obese individuals who were prescribed an energy-restricted diet that delivered a greater ratio of protein relative to carbohydrate. Greater amounts of fat were lost when higher amounts of protein were ingested, but even greater amounts of fat loss occurred when the exercise program was added to the high-protein diet group, resulting in significant decreases in body fat.
Each person was randomly assigned to consume a diet that contained either 1× 0. Participants were measured for changes in body weight and body composition.
While the greatest body weight loss occurred in the 1× RDA group, this group also lost the highest percentage of fat-free mass and lowest percentage of fat mass. Collectively, these results indicate that increasing dietary protein can promote favorable adaptations in body composition through the promotion of fat-free mass accretion when combined with a hyperenergetic diet and a heavy resistance training program and can also promote the loss of fat mass when higher intakes of daily protein × the RDA are combined with an exercise program and a hypoenergetic diet.
When combined with a hyperenergetic diet and a heavy resistance-training program, protein supplementation may promote increases in skeletal muscle cross-sectional area and lean body mass. When combined with a resistance-training program and a hypoenergetic diet, an elevated daily intake of protein 2 — 3× the RDA can promote greater losses of fat mass and greater overall improvements in body composition.
In the absence of feeding, muscle protein balance remains negative in response to an acute bout of resistance exercise [ 48 ]. Tipton et al. Later, Burd et al.
Subsequently, these conclusions were supported by Borsheim [ 52 ] and Volpi [ 53 ]. The study by Borsheim also documented a dose-response outcome characterized by a near doubling of net protein balance in response to a three to six gram dose of the EAAs [ 52 ]. Building on this work, Tipton et al.
These findings formed the theoretical concept of protein timing for resistance exercise that has since been transferred to not only other short-duration, high-intensity activities [ 56 ] but also endurance-based sports [ 57 ] and subsequent performance outcomes [ 58 ].
The strategic consumption of nutrition, namely protein or various forms of amino acids, in the hours immediately before and during exercise i. While earlier investigations reported positive effects from consumption of amino acids [ 37 , 46 , 61 ], it is now clear that intact protein supplements such as egg, whey, casein, beef, soy and even whole milk can evoke an anabolic response that can be similar or greater in magnitude to free form amino acids, assuming ingestion of equal EAA amounts [ 62 , 63 , 64 ].
For instance, whey protein ingested close to resistance exercise, promotes a higher activation phosphorylation of mTOR a key signaling protein found in myocytes that is linked to the synthesis of muscle proteins and its downstream mRNA translational signaling proteins i.
Moreover, it was found that the increased mTOR signaling corresponded with significantly greater muscle hypertrophy after 10 weeks of training [ 65 ]. However, the hypertrophic differences between protein consumption and a non-caloric placebo appeared to plateau by week 21, despite a persistently greater activation of this molecular signaling pathway from supplementation.
Results from other research groups [ 56 , 57 , 58 , 66 ] show that timing of protein near ± 2 h aerobic and anaerobic exercise training appears to provide a greater activation of the molecular signalling pathways that regulate myofibrillar and mitochondrial protein synthesis as well as glycogen synthesis.
It is widely reported that protein consumption directly after resistance exercise is an effective way to acutely promote a positive muscle protein balance [ 31 , 55 , 67 ], which if repeated over time should translate into a net gain or hypertrophy of muscle [ 68 ]. Pennings and colleagues [ 69 ] reported an increase in both the delivery and incorporation of dietary proteins into the skeletal muscle of young and older adults when protein was ingested shortly after completion of exercise.
These findings and others add to the theoretical basis for consumption of post-protein sooner rather than later after exercise, since post workout MPS rates peak within three hours and remain elevated for an additional 24—72 h [ 50 , 70 ].
This extended time frame also provides a rationale for both immediate and sustained i. These temporal considerations would also capture the peak elevation in signalling proteins shown to be pivotal for increasing the initiation of translation of muscle proteins, which for the most part appears to peak between 30 and 60 min after exercise [ 71 ].
However, these differences may be related to the type of protein used between the studies. The studies showing positive effects of protein timing used milk proteins, whereas the latter study used a collagen based protein supplement.
While a great deal of work has focused on post-exercise protein ingestion, other studies have suggested that pre-exercise and even intra-exercise ingestion may also support favorable changes in MPS and muscle protein breakdown [ 14 , 54 , 75 , 76 , 77 , 78 ].
Initially, Tipton and colleagues [ 54 ] directly compared immediate pre-exercise and immediate post-exercise ingestion of a mixture of carbohydrate 35 g and EAAs 6 g combination on changes in MPS. They reported that pre-exercise ingestion promoted higher rates of MPS while also demonstrating that nutrient ingestion prior to exercise increased nutrient delivery to a much greater extent than other immediate or one hour post-exercise time points.
These results were later challenged by Fujita in who employed an identical study design with a different tracer incorporation approach and concluded there was no difference between pre- or post-exercise ingestion [ 75 ].
Subsequent work by Tipton [ 79 ] also found that similar elevated rates of MPS were achieved when ingesting 20 g of a whey protein isolate immediately before or immediately after resistance exercise. At this point, whether any particular time of protein ingestion confers any unique advantage over other time points throughout a h day to improve strength and hypertrophy has yet to be adequately investigated.
To date, although a substantial amount of literature discusses this concept [ 60 , 80 ], a limited number of training studies have assessed whether immediate pre- and post-exercise protein consumption provides unique advantages compared to other time points [ 72 , 73 , 81 ].
Each study differed in population, training program, environment and nutrition utilized, with each reporting a different result.
What is becoming clear is that the subject population, nutrition habits, dosing protocols on both training and non-training days, energy and macronutrient intake, as well as the exercise bout or training program itself should be carefully considered alongside the results.
In particular, the daily amount of protein intake seems to operate as a key consideration because the benefits of protein timing in relation to the peri-workout period seem to be lessened for people who are already ingesting appropriate amounts of protein e.
A literature review by Aragon and Schoenfeld [ 83 ] determined that while compelling evidence exists showing muscle is sensitized to protein ingestion following training, the increased sensitivity to protein ingestion might be greatest in the first five to six hours following exercise.
Thus, the importance of timing may be largely dependent on when a pre-workout meal was consumed, the size and composition of that meal and the total daily protein in the diet.
In this respect, a pre-exercise meal will provide amino acids during and after exercise and therefore it stands to reason there is less need for immediate post-exercise protein ingestion if a pre-exercise meal is consumed less than five hours before the anticipated completion of a workout.
A meta-analysis by Schoenfeld et al. The authors concluded that total protein intake was the strongest predictor of muscular hypertrophy and that protein timing likely influences hypertrophy to a lesser degree.
However, the conclusions from this meta-analysis may be questioned because the majority of the studies analyzed were not protein timing studies but rather protein supplementation studies. In that respect, the meta-analysis provides evidence that protein supplementation i.
While a strong rationale remains to support the concept that the hours immediately before or after resistance exercise represents an opportune time to deliver key nutrients that will drive the accretion of fat-free mass and possibly other favorable adaptations, the majority of available literature suggests that other factors may indeed be operating to a similar degree that ultimately impact the observed adaptations.
In this respect, a key variable that must be accounted for is the absolute need for energy and protein required to appropriately set the body up to accumulate fat-free mass. Thus, the most practical recommendation is to have athletes consume a meal during the post-workout or pre-workout time period since it may either help or have a neutral effect.
In younger subjects, the ingestion of 20—30 g of any high biological value protein before or after resistance exercise appears to be sufficient to maximally stimulate MPS [ 21 , 64 ]. More recently, Macnaughton and colleagues [ 85 ] reported that 40 g of whey protein ingestion significantly increased the MPS responses compared to a 20 g feeding after an acute bout of whole-body resistance exercise, and that the absolute protein dose may operate as a more important consideration than providing a protein dose that is normalized to lean mass.
Free form EAAs, soy, milk, whey, caseinate, and other protein hydrolysates are all capable of activating MPS [ 86 ]. However, maximal stimulation of MPS, which results in higher net muscle protein accretion, is the product of the total amount of EAA in circulation as well as the pattern and appearance rate of aminoacidemia that modulates the MPS response [ 86 ].
Recent work has clarified that whey protein provides a distinct advantage over other protein sources including soy considered another fast absorbing protein and casein a slower acting protein source on acute stimulation of MPS [ 86 , 87 ].
Importantly, an elegant study by West and investigators [ 87 ] sought to match the delivery of EAAs in feeding patterns that replicated how whey and casein are digested.
The authors reported that a 25 g dose of whey protein that promoted rapid aminoacidemia further enhanced MPS and anabolic signaling when compared to an identical total dose of whey protein when delivered as ten separate 2. The advantages of whey protein are important to consider, particularly as all three sources rank similarly in assessments of protein quality [ 88 ].
In addition to soy, other plant sources e. have garnered interest as potential protein sources to consider.
Unfortunately, research that examines the ability of these protein sources to modulate exercise performance and training adaptations is limited at this time. The investigators concluded that gains in strength, muscle thickness and body composition were similar between the two protein groups, suggesting that rice protein may be a suitable alternative to whey protein at promoting resistance training adaptations.
Furthermore, differences in absorption kinetics, and the subsequent impact on muscle protein metabolism appear to extend beyond the degree of hydrolysis and amino acid profiles [ 69 , 86 , 90 , 91 , 92 , 92 ]. For instance, unlike soy more of the EAAs from whey proteins hydrolysates and isolates survive splanchnic uptake and travel to the periphery to activate a higher net gain in muscle [ 86 ].
These characteristics yield a high concentration of amino acids in the blood aminoacidemia [ 69 , 87 ] that facilitates greater activation of MPS and net muscle protein accretion, in direct comparison to other protein choices [ 50 , 69 , 91 ].
The addition of creatine to whey protein supplementation appears to further augment these adaptations [ 27 , 72 , 95 ]; however, an optimal timing strategy for this combination remains unclear.
The timing of protein-rich meals consumed throughout a day has the potential to influence adaptations to exercise. Using similar methods, other studies over recent decades [ 53 , 62 , 87 , 91 , 96 , 97 , 98 , 99 , ] have established the following:. The anabolic response to feeding is pronounced but transient.
During the post-prandial phase 1—4 h after a meal MPS is elevated, resulting in a positive muscle protein balance. In contrast, MPS rates are lower in a fasted state and muscle protein balance is negative. Protein accretion only occurs in the fed state. The concentration of EAA in the blood plasma regulates protein synthesis rates within muscle at rest and post exercise.
More recent work has established that protein-carbohydrate supplementation after strenuous endurance exercise stimulates contractile MPS via similar signaling pathways as resistance exercise [ 56 , 57 ]. That is, the consumption of a protein-containing meal up to 24 h after a single bout of resistance exercise results in a higher net stimulation of MPS and protein accretion than the same meal consumed after 24 h of inactivity [ 50 ].
The effect of insulin on MPS is dependent on its ability to increase amino acid availability, which does not occur when insulin is systematically increased e.
Taken together, these results seem to indicate that post-workout carbohydrate supplementation offers very little contribution from a muscle development standpoint provided adequate protein is consumed. Importantly, these results are not to be interpreted to mean that carbohydrate administration offers no potential effect for an athlete engaging in moderate to high volumes of training, but rather that benefits derived from carbohydrate administration appear to more favorably impact aspects of muscle glycogen recovery as opposed to stimulating muscle protein accretion.
Eating before sleep has long been controversial [ , , ]. However, a methodological consideration in the original studies such as the population used, time of feeding, and size of the pre-sleep meal confounds firm conclusions about benefits or drawbacks.
Results from several investigations indicate that 30—40 g of casein protein ingested min prior to sleep [ ] or via nasogastric tubing [ ] increased overnight MPS in both young and old men, respectively. Likewise, in an acute setting, 30 g of whey protein, 30 g of casein protein, and 33 g of carbohydrate consumed min prior to sleep resulted in an elevated morning resting metabolic rate in young fit men compared to a non-caloric placebo [ ].
Interestingly, Madzima et al. This infers that casein protein consumed pre-sleep maintains overnight lipolysis and fat oxidation. This finding was further supported by Kinsey et al. Similar to Madzima et al.
Interestingly, the pre-sleep protein and carbohydrate ingestion resulted in elevated insulin concentrations the next morning and decreased hunger in this overweight population. Of note, it appears that exercise training completely ameliorates any rise in insulin when eating at night before sleep [ ], while the combination of pre-sleep protein and exercise has been shown to reduce blood pressure and arterial stiffness in young obese women with prehypertension and hypertension [ ].
In athletes, evening chocolate milk consumption has also been shown to influence carbohydrate metabolism in the morning, but not running performance [ ]. In addition, data supports that exercise performed in the evening augments the overnight MPS response in both younger and older men [ , , ].
To date, only a few studies involving nighttime protein ingestion have been carried out for longer than four weeks. Snijders et al. The group receiving the protein-centric supplement each night before sleep had greater improvements in muscle mass and strength over the week study.
Of note, this study was non-nitrogen balanced and the protein group received approximately 1. More recently, in a study in which total protein intake was equal, Antonio et al.
They examined the effects on body composition and performance [ ]. All subjects maintained their usual exercise program. The authors reported no differences in body composition or performance between the morning and evening casein supplementation groups.
However, it is worth noting that, although not statistically significant, the morning group added 0. Although this finding was not statistically significant, it supports data from Burk et al.
It should be noted that the subjects in the Burk et al. study were resistance training. A retrospective epidemiological study by Buckner et al. Thus, it appears that protein consumption in the evening before sleep might be an underutilized time to take advantage of a protein feeding opportunity that can potentially improve body composition and performance.
In addition to direct assessments of timed administration of nutrients, other studies have explored questions that center upon the pattern of when certain protein-containing meals are consumed.
Paddon-Jones et al. In this study, participants were given an EAA supplement three times a day for 28 days. Results indicated that acute stimulation of MPS provided by the supplement on day 1 resulted in a net gain of ~7.
When extrapolated over the entire day study, the predicted change in muscle mass corresponded to the actual change in muscle mass ~ g measured by dual-energy x-ray absorptiometry DEXA [ 97 ]. While these findings are important, it is vital to highlight that this study incorporated a bed rest model with no acute exercise stimulus while other work by Mitchell et al.
Interestingly, supplementation with 15 g of EAAs and 30 g of carbohydrate produced a greater anabolic effect increase in net phenylalanine balance than the ingestion of a mixed macronutrient meal, despite the fact that both interventions contained a similar dose of EAAs [ 96 ].
Most importantly, the consumption of the supplement did not interfere with the normal anabolic response to the meal consumed three hours later [ 96 ]. Areta et al. The researchers compared the anabolic responses of three different patterns of ingestion a total of 80 g of protein throughout a h recovery period after resistance exercise.
Using a group of healthy young adult males, the protein feeding strategies consisted of small pulsed 8 × 10 g , intermediate 4 × 20 g , or bolus 2 × 40 g administration of whey protein over the h measurement window. Results showed that the intermediate dosing 4 × 20 g was superior for stimulating MPS for the h experimental period.
Specifically, the rates of myofibrillar protein synthesis were optimized throughout the day of recovery by the consumption of 20 g protein every three hours compared to large 2 × 40 g , less frequent servings or smaller but more frequent 8 × 10 g patterns of protein intake [ 67 ].
Previously, the effect of various protein feeding strategies on skeletal MPS during an entire day was unknown. This study provided novel information demonstrating that the regulation of MPS can be modulated by the timing and distribution of protein over 12 h after a single bout of resistance exercise.
However, it should be noted that an 80 g dose of protein over a h period is quite low. The logical next step for researchers is to extend these findings into longitudinal training studies to see if these patterns can significantly affect resistance-training adaptations.
Indeed, published studies by Arnal [ ] and Tinsley [ ] have all made some attempt to examine the impact of adjusting the pattern of protein consumption across the day in combination with various forms of exercise. Collective results from these studies are mixed.
Thus, future studies in young adults should be designed to compare a balanced vs. skewed distribution pattern of daily protein intake on the daytime stimulation of MPS under resting and post-exercise conditions and training-induced changes in muscle mass, while taking into consideration the established optimal dose of protein contained in a single serving for young adults.
Without more conclusive evidence spanning several weeks, it seems pragmatic to recommend the consumption of at least g of protein ~0. In the absence of feeding and in response to resistance exercise, muscle protein balance remains negative.
Skeletal muscle is sensitized to the effects of protein and amino acids for up to 24 h after completion of a bout of resistance exercise. A protein dose of 20—40 g of protein 10—12 g of EAAs, 1—3 g of leucine stimulates MPS, which can help to promote a positive nitrogen balance.
The EAAs are critically needed for achieving maximal rates of MPS making high-quality, protein sources that are rich in EAAs and leucine the preferred sources of protein. Studies have suggested that pre-exercise feedings of amino acids in combination with carbohydrate can achieve maximal rates of MPS, but protein and amino acid feedings during this time are not clearly documented to increase exercise performance.
Total protein and calorie intake appears to be the most important consideration when it comes to promoting positive adaptations to resistance training, and the impact of timing strategies immediately before or immediately after to heighten these adaptations in non-athletic populations appears to be minimal.
Proteins provide the building blocks of all tissues via their constituent amino acids. Athletes consume dietary protein to repair and rebuild skeletal muscle and connective tissues following intense training bouts or athletic events. A report in by Phillips [ ] summarized the findings surrounding protein requirements in resistance-trained athletes.
Using a regression approach, he concluded that a protein intake of 1. A key consideration regarding these recommended values is that all generated data were obtained using the nitrogen balance technique, which is known to underestimate protein requirements.
Interestingly, two of the included papers had prescribed protein intakes of 2. All data points from these two studies also had the highest levels of positive nitrogen balance. For an athlete seeking to ensure an anabolic environment, higher daily protein intakes might be needed.
Another challenge that underpins the ability to universally and successfully recommend daily protein amounts are factors related to the volume of the exercise program, age, body composition and training status of the athlete; as well as the total energy intake in the diet, particularly for athletes who desire to lose fat and are restricting calories to accomplish this goal [ ].
For these reasons, and due to an increase of published studies in areas related to optimal protein dosing, timing and composition, protein needs are being recommended within this position stand on a per meal basis. For example, Moore [ 31 ] found that muscle and albumin protein synthesis was optimized at approximately 20 g of egg protein at rest.
Witard et al. Furthermore, while results from these studies offer indications of what optimal absolute dosing amounts may be, Phillips [ ] concluded that a relative dose of 0.
Once a total daily target protein intake has been achieved, the frequency and pattern with which optimal doses are ingested may serve as a key determinant of overall changes in protein synthetic rates. Research indicates that rates of MPS rapidly rise to peak levels within 30 min of protein ingestion and are maintained for up to three hours before rapidly beginning to lower to basal rates of MPS even though amino acids are still elevated in the blood [ ].
Using an oral ingestion model of 48 g of whey protein in healthy young men, rates of myofibrillar protein synthesis increased three-fold within 45—90 min before slowly declining to basal rates of MPS all while plasma concentration of EAAs remained significantly elevated [ ].
While largely unexplored in a human model, these authors relied upon an animal model and were able to reinstate increases in MPS using the consumption of leucine and carbohydrate min after ingestion of the first meal. As such, it is suggested that individuals attempting to restrict caloric intake should consume three to four whole meals consisting of 20—40 g of protein per meal.
While this recommendation stems primarily from initial work that indicated protein doses of 20—40 g favorably promote increased rates of MPS [ 31 , , ], Kim and colleagues [ ] recently reported that a 70 g dose of protein promoted a more favorable net balance of protein when compared to a 40 g dose due to a stronger attenuation of rates of muscle protein breakdown.
For those attempting to increase their calories, we suggest consuming small snacks between meals consisting of both a complete protein and a carbohydrate source.
This contention is supported by research from Paddon-Jones et al. These researchers compared three cal mixed macronutrient meals to three cal meals combined with three cal amino acid-carbohydrate snacks between meals.
Additionally, using a protein distribution pattern of 20—25 g doses every three hours in response to a single bout of lower body resistance exercise appears to promote the greatest increase in MPS rates and phosphorylation of key intramuscular proteins linked to muscle hypertrophy [ ].
This simple addition could provide benefits for individuals looking to increase muscle mass and improve body composition in general while also striving to maintain or improve health and performance. The current RDA for protein is 0. While previous recommendations have suggested a daily intake of 1.
Daily and per dose needs are combinations of many factors including volume of exercise, age, body composition, total energy intake and training status of the athlete. Daily intakes of 1. Even higher amounts ~70 g appear to be necessary to promote attenuation of muscle protein breakdown.
Pacing or spreading these feeding episodes approximately three hours apart has been consistently reported to promote sustained, increased levels of MPS and performance benefits. There are 20 total amino acids, comprised of 9 EAAs and 11 non-essential amino acids NEAAs.
EAAs cannot be produced in the body and therefore must be consumed in the diet. Several methods exist to determine protein quality such as Chemical Score, Protein Efficiency Ratio, Biological Value, Protein Digestibility-Corrected Amino Acid Score PDCAAS and most recently, the Indicator Amino Acid Oxidation IAAO technique.
Ultimately, in vivo protein quality is typically defined as how effective a protein is at stimulating MPS and promoting muscle hypertrophy [ ]. Overall, research has shown that products containing animal and dairy-based proteins contain the highest percentage of EAAs and result in greater hypertrophy and protein synthesis following resistance training when compared to a vegetarian protein-matched control, which typically lacks one or more EAAs [ 86 , 93 , ].
Several studies, but not all, [ ] have indicated that EAAs alone stimulate protein synthesis in the same magnitude as a whole protein with the same EAA content [ 98 ].
For example, Borsheim et al. Moreover, Paddon-Jones and colleagues [ 96 ] found that a cal supplement containing 15 g of EAAs stimulated greater rates of protein synthesis than an cal meal with the same EAA content from a whole protein source.
While important, the impact of a larger meal on changes in circulation and the subsequent delivery of the relevant amino acids to the muscle might operate as important considerations when interpreting this data. In contrast, Katsanos and colleagues [ ] had 15 elderly subjects consume either 15 g of whey protein or individual doses of the essential and nonessential amino acids that were identical to what is found in a g whey protein dose on separate occasions.
Whey protein ingestion significantly increased leg phenylalanine balance, an index of muscle protein accrual, while EAA and NEAA ingestion exerted no significant impact on leg phenylalanine balance.
This study, and the results reported by others [ ] have led to the suggestion that an approximate 10 g dose of EAAs might serve as an optimal dose to maximally stimulate MPS and that intact protein feedings of appropriate amounts as opposed to free amino acids to elderly individuals may stimulate greater improvements in leg muscle protein accrual.
Based on this research, scientists have also attempted to determine which of the EAAs are primarily responsible for modulating protein balance. The three branched-chain amino acids BCAAs , leucine, isoleucine, and valine are unique among the EAAs for their roles in protein metabolism [ ], neural function [ , , ], and blood glucose and insulin regulation [ ].
Additionally, enzymes responsible for the degradation of BCAAs operate in a rate-limiting fashion and are found in low levels in splanchnic tissues [ ].
Thus, orally ingested BCAAs appear rapidly in the bloodstream and expose muscle to high concentrations ultimately making them key components of skeletal MPS [ ].
Furthermore, Wilson and colleagues [ ] have recently demonstrated, in an animal model, that leucine ingestion alone and with carbohydrate consumed between meals min post-consumption extends protein synthesis by increasing the energy status of the muscle fiber.
Multiple human studies have supported the contention that leucine drives protein synthesis [ , ]. Moreover, this response may occur in a dose-dependent fashion, plateauing at approximately two g at rest [ 31 , ], and increasing up to 3.
However, it is important to realize that the duration of protein synthesis after resistance exercise appears to be limited by both the signal leucine concentrations , ATP status, as well as the availability of substrate i.
As such, increasing leucine concentration may stimulate increases in muscle protein, but a higher total dose of all EAAs as free form amino acids or intact protein sources seems to be most suited for sustaining the increased rates of MPS [ ].
It is well known that exercise improves net muscle protein balance and in the absence of protein feeding, this balance becomes more negative. When combined with protein feeding, net muscle protein balance after exercise becomes positive [ ]. Norton and Layman [ ] proposed that consumption of leucine, could turn a negative protein balance to a positive balance following an intense exercise bout by prolonging the MPS response to feeding.
In support, the ingestion of a protein or essential amino acid complex that contains sufficient amounts of leucine has been shown to shift protein balance to a net positive state after intense exercise training [ 46 , ].
Even though leucine has been demonstrated to independently stimulate protein synthesis, it is important to recognize that supplementation should not be with just leucine alone. For instance, Wilson et al.
In summary, athletes should focus on consuming adequate leucine content in each of their meals through selection of high-quality protein sources [ ]. Protein sources containing higher levels of the EAAs are considered to be higher quality sources of protein.
The body uses 20 amino acids to make proteins, seven of which are essential nine conditionally , requiring their ingestion to meet daily needs. EAAs appear to be uniquely responsible for increasing MPS with doses ranging from 6 to 15 g all exerting stimulatory effects.
In addition, doses of approximately one to three g of leucine per meal appear to be needed to stimulate protein translation machinery. The BCAAs i. However, the extent to which these changes are aligned with changes in MPS remains to be fully explored. While greater doses of leucine have been shown to independently stimulate increases in protein synthesis, a balanced consumption of the EAAs promotes the greatest increases.
Milk proteins have undergone extensive research related to their potential roles in augmenting adaptations from exercise training [ 86 , 93 ]. For example, consuming milk following exercise has been demonstrated to accelerate recovery from muscle damaging exercise [ ], increase glycogen replenishment [ ], improve hydration status [ , ], and improve protein balance to favor synthesis [ 86 , 93 ], ultimately resulting in increased gains in both neuromuscular strength and skeletal muscle hypertrophy [ 93 ].
Moreover, milk protein contains the highest score on the PDCAAS rating system, and in general contains the greatest density of leucine [ ]. Milk can be fractionated into two protein classes, casein and whey. While both are high in quality, the two differ in the rate at which they digest as well as the impact they have on protein metabolism [ , , ].
Whey protein is water soluble, mixes easily, and is rapidly digested [ ]. In contrast, casein is water insoluble, coagulates in the gut and is digested more slowly than whey protein [ ].
Casein also has intrinsic properties such as opioid peptides, which effectively slow gastric motility [ ]. Original research investigating the effects of digestion rate was conducted by Boirie, Dangin and colleagues [ , , ].
These researchers gave a 30 g bolus of whey protein and a 43 g bolus of casein protein to subjects on separate occasions and measured amino acid levels for several hours after ingestion. They reported that the whey protein condition displayed robust hyperaminoacidemia min after administration.
However, by min, amino acid concentrations had returned to baseline. In contrast, the casein condition resulted in a slow increase in amino acid concentrations, which remained elevated above baseline after min. Over the study duration, casein produced a greater whole body leucine balance than the whey protein condition, leading the researcher to suggest that prolonged, moderate hyperaminoacidemia is more effective at stimulating increases in whole body protein anabolism than a robust, short lasting hyperaminoacidemia.
While this research appears to support the efficacy of slower digesting proteins, subsequent work has questioned its validity in athletes. The first major criticism is that Boire and colleagues investigated whole body non-muscle and muscle protein balance instead of skeletal myofibrillar MPS.
These findings suggest that changes in whole body protein turnover may poorly reflect the level of skeletal muscle protein metabolism that may be taking place. Trommelen and investigators [ ] examined 24 young men ingesting 30 g of casein protein with or without completion of a single bout of resistance exercise, and concluded that rates of MPS were increased, but whole-body protein synthesis rates were not impacted.
More recently, Tang and colleagues [ 86 ] investigated the effects of administering 22 g of hydrolyzed whey isolate and micellar casein 10 g of EAAs at both rest and following a single bout of resistance training in young males.
Moreover, these researchers reported that whey protein ingestion stimulated greater MPS at both rest and following exercise when compared to casein. In comparison to the control group, both whey and casein significantly increased leucine balance, but no differences were found between the two protein sources for amino acid uptake and muscle protein balance.
Additional research has also demonstrated that 10 weeks of whey protein supplementation in trained bodybuilders resulted in greater gains in lean mass 5.
These findings suggest that the faster-digesting whey proteins may be more beneficial for skeletal muscle adaptations than the slower digesting casein. Skeletal muscle glycogen stores are a critical element to both prolonged and high-intensity exercise.
In skeletal muscle, glycogen synthase activity is considered one of the key regulatory factors for glycogen synthesis. Research has demonstrated that the addition of protein in the form of milk and whey protein isolate 0.
Further, the addition of protein facilitates repair and recovery of the exercised muscle [ 12 ]. These effects are thought to be related to a greater insulin response following the exercise bout.
Intriguingly, it has also been demonstrated that whey protein enhances glycogen synthesis in the liver and skeletal muscle more than casein in an insulin-independent fashion that appears to be due to its capacity to upregulate glycogen synthase activity [ ]. Therefore, the addition of milk protein to a post-workout meal may augment recovery, improve protein balance, and speed glycogen replenishment.
While athletes tend to view whey as the ideal protein for skeletal muscle repair and function it also has several health benefits. In particular, whey protein contains an array of biologically active peptides whose amino acids sequences give them specific signaling effects when liberated in the gut.
Furthermore, whey protein appears to play a role in enhancing lymphatic and immune system responses [ ]. In addition, α-lactalbumin contains an ample supply of tryptophan which increases cognitive performance under stress [ ], improves the quality of sleep [ , ], and may also speed wound healing [ ], properties which could be vital for recovery from combat and contact sporting events.
In addition, lactoferrin is also found in both milk and in whey protein, and has been demonstrated to have antibacterial, antiviral, and antioxidant properties [ ]. Moreover, there is some evidence that whey protein can bind iron and therefore increase its absorption and retention [ ].
Egg protein is often thought of as an ideal protein because its amino acid profile has been used as the standard for comparing other dietary proteins [ ]. Due to their excellent digestibility and amino acid content, eggs are an excellent source of protein for athletes.
While the consumption of eggs has been criticized due to their cholesterol content, a growing body of evidence demonstrates the lack of a relationship between egg consumption and coronary heart disease, making egg-based products more appealing [ ]. One large egg has 75 kcal and 6 g of protein, but only 1.
Research using eggs as the protein source for athletic performance and body composition is lacking, perhaps due to less funding opportunities relative to funding for dairy.
Egg protein may be particularly important for athletes, as this protein source has been demonstrated to significantly increase protein synthesis of both skeletal muscle and plasma proteins after resistance exercise at both 20 and 40 g doses.
Leucine oxidation rates were found to increase following the 40 g dose, suggesting that this amount exceeds an optimal dose [ 31 ]. Dietary Reference Intakes: Energy, Carbohydrates, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids.
Washington, DC: National Academies Press; Fink HH, Burgoon LA, Mikesky AE. Endurance and Ultra-Endurance Athletes: Practical Applications in Sports Nutrition. Sudbury, MA: Jones and Bartlett; Phillips SM, Van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation.
J Sports Sci. Colombani PC, Mettler S. Role of dietary proteins in sports. Int J Vitam Nutr Res. Timmerman KL, Dhanani S, Glynn EL, et al. A moderate acute increase in physical activity enhances nutritive flow and the muscle protein anabolic response to mixed nutrient intake in older adults.
Am J Clin Nutr. Campbell B, Kreider RB, Ziegenfuss T, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. Layman DK. Protein nutrition, meal timing, and muscle health.
In: Berdanier CD, Dwyer JT, Heber D, eds. Handbook of Nutrition and Food. Boca Raton, FL: CRC Press; USDA National Nutrient Database for Standard Reference, Release US Department of Agriculture Agricultural Service website.
Poole C, Wilborn C, Taylor L, Kerksick C. The role of post-exercise nutrient administration on muscle protein synthesis and glycogen synthesis. J Sports Sci Med. Phillips SM. Dietary protein requirements and adaptive advantages in athletes. Br J Nutr. Burd NA, West DW, Moore DR, et al.
Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men.
J Nutr. Mamerow MM, Mettler JA, English KL, et al. Dietary protein distribution positively influences h muscle protein synthesis in healthy adults [published online January 29, ]. doi: Energy intakes: percentages of energy from protein, carbohydrate, fat, and alcohol, by gender and age, what we eat in America, NHANES
Adolescent athletes Glucose metabolism rate adequate energy and PProtein Protein intake for athletes to support growth, Protein intake for athletes, and the demands associated with infake and training. However, they are athleres to nutritional inadequacies affecting their athletees and physical performance. Food choices with nutrient adequacy and environmental protection is crucial for a sustainable diet. Therefore, we aimed to assess the adequacy of low-carbon diets to meet the protein requirements of adolescent athletes. Therefore, a cross-sectional observational study was conducted with 91 adolescent athletes from sports clubs in Rio de Janeiro who underwent anthropometric and food consumption assessments.
Jonathan Valdez, RDN, CDCES, CPT is a Nitake York Online resupply solutions telehealth athletrs dietitian Protein intake for athletes and athlstes communications expert. You hear a lot about athletes and protein. And while it's true that some vor who participate in strenuous exercise may Protein intake for athletes a slightly increased Protein intake for athletes to athleres some quality protein in their diet, it may not be as much as you think. All the energy we need to maintain our body and mind, as well as the fuel to help us exercise comes from the foods we eat and the fluids we drink. To determine the right amount of calories, and nutrients to consume, it's helpful to consider how we use our energy stores on a daily basis and replace energy accordingly. It's also helpful to understand the main groupings of nutrients in the typical diet.
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