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 ]. In addition to providing a cost effective, high-quality source of protein rich in leucine 0.

Functional foods are defined as foods that, by the presence of physiologically active components, provide a health benefit beyond basic nutrition [ ]. According to the Academy of Nutrition and Dietetics, functional foods should be consumed as part of a varied diet on a regular basis, at effective levels [ ].

Thus, it is essential that athletes select foods that meet protein requirements and also optimize health and prevent decrements in immune function following intense training. Eggs are also rich in choline, a nutrient which may have positive effects on cognitive function [ ].

Moreover, eggs provide an excellent source of the carotenoid-based antioxidants lutein and zeaxanthin [ ]. Also, eggs can be prepared with most meal choices, whether at breakfast, lunch, or dinner.

Such positive properties increase the probability of the athletes adhering to a diet rich in egg protein. Meat proteins are a major staple in the American diet and, depending on the cut of meat, contain varying amounts of fat and cholesterol.

Meat proteins are well known to be rich sources of the EAAs [ ]. Beef is a common source of dietary protein and is considered to be of high biological value because it contains the full balance of EAAs in a fraction similar to that found in human skeletal muscle [ ].

A standard serving of Moreover, this 30 g dose of beef protein has been shown to stimulate protein synthesis in both young and elderly subjects [ ].

In addition to its rich content of amino acids, beef and other flesh proteins can serve as important sources of micronutrients such as iron, selenium, vitamins A, B12 and folic acid. This is a particularly important consideration for pregnant and breastfeeding women.

Ultimately, as an essential part of a mixed diet, meat helps to ensure adequate distribution of essential micronutrients and amino acids to the body. Research has shown that significant differences in skeletal muscle mass and body composition between older men who resistance train and either consume meat-based or lactoovovegetarian diet [ ].

Over a week period, whole-body density, fat-free mass, and whole-body muscle mass as measured by urinary creatinine excretion increased in the meat-sourced diet group but decreased in the lactoovovegetarian diet group.

These results indicate that not only do meat-based diets increase fat-free mass, but also they may specifically increase muscle mass, thus supporting the many benefits of meat-based diets.

A diet high in meat protein in older adults may provide an important resource in reducing the risk of sarcopenia. Positive results have also been seen in elite athletes that consume meat-based proteins, as opposed to vegetarian diets [ ]. For example, carnitine is a molecule that transports long-chain fatty acids into mitochondria for oxidation and is found in high amounts in meat.

While evidence is lacking to support an increase in fat oxidation with increased carnitine availability, carnitine has been linked to the sparing of muscle glycogen, and decreases in exercise-induced muscle damage [ ]. Certainly, more research is needed to support these assertions.

Creatine is a naturally occurring compound found mainly in muscle. Vegetarians have lower total body creatine stores than omnivores, which demonstrates that regular meat eating has a significant effect on human creatine status [ ].

Moreover, creatine supplementation studies with vegetarians indicate that increased creatine uptake levels do exist in people who practice various forms of vegetarianism [ ]. Sharp and investigators [ ] published the only study known to compare different supplemental powdered forms of animal proteins on adaptations to resistance training such as increases in strength and improvements in body composition.

Forty-one men and women performed a standardized resistance-training program over eight weeks and consumed a daily 46 g dose of either hydrolyzed chicken protein, beef protein isolate, or whey protein concentrate in comparison to a control group.

All groups experienced similar increases in upper and lower-body strength, but all protein-supplemented groups reported significant increases in lean mass and decreases in fat mass. Meat-based diets have been shown to include additional overall health benefits. Some studies have found that meat, as a protein source, is associated with higher serum levels of IGF-1 [ ], which in turn is related to increased bone mineralization and fewer fractures [ ].

A highly debated topic in nutrition and epidemiology is whether vegetarian diets are a healthier choice than omnivorous diets. One key difference is the fact that vegetarian diets often lack equivalent amounts of protein when compared to omnivorous diets [ ].

However, with proper supplementation and careful nutritional choices, it is possible to have complete proteins in a vegetarian diet. Generally by consuming high-quality, animal-based products meat, milk, eggs, and cheese an individual will achieve optimal growth as compared to ingesting only plant proteins [ ].

Research has shown that soy is considered a lower quality complete protein. Hartman et al. They found that the participants that consumed the milk protein increased lean mass and decreased fat mass more than the control and soy groups.

Moreover, the soy group was not significantly different from the control group. Similarly, a study by Tang and colleagues [ 86 ] directly compared the abilities of hydrolyzed whey isolate, soy isolate, and micellar casein to stimulate rates of MPS both at rest and in response to a single bout of lower body resistance training.

These authors reported that the ability of soy to stimulate MPS was greater than casein, but less than whey, at rest and in response to an acute resistance exercise stimulus. While soy is considered a complete protein, it contains lower amounts of BCAAs than bovine milk [ ]. Additionally, research has found that dietary soy phytoestrogens inhibit mTOR expression in skeletal muscle through activation of AMPK [ ].

Thus, not only does soy contain lower amounts of the EAAs and leucine, but soy protein may also be responsible for inhibiting growth factors and protein synthesis via its negative regulation of mTOR.

When considering the multitude of plant sources of protein, soy overwhelmingly has the most research. Limited evidence using wheat protein in older men has suggested that wheat protein stimulates significantly lower levels of MPS when compared to an identical dose 35 g of casein protein, but when this dose is increased nearly two fold 60 g this protein source is able to significantly increase rates of myofibrillar protein synthesis [ ].

As mentioned earlier, a study by Joy and colleagues [ 89 ] in which participants participated in resistance training program for eight weeks while taking identical, high doses of either rice or whey protein, demonstrated that rice protein stimulated similar increases in body composition adaptations to whey protein.

The majority of available science has explored the efficacy of ingesting single protein sources, but evidence continues to mount that combining protein sources may afford additional benefits [ ].

For example, a week resistance training study by Kerksick and colleagues [ 22 ] demonstrated that a combination of whey 40 g and casein 8 g yielded the greatest increase in fat-free mass determined by DEXA when compared to both a combination of 40 g of whey, 5 g of glutamine, and 3 g of BCAAs and a placebo consisting of 48 g of a maltodextrin carbohydrate.

Later, Kerksick et al. Similarly, Hartman and investigators [ 93 ] had 56 healthy young men train for 12 weeks while either ingesting isocaloric and isonitrogenous doses of fat-free milk a blend of whey and casein , soy protein or a carbohydrate placebo and concluded that fat-free milk stimulated the greatest increases in Type I and II muscle fiber area as well as fat-free mass; however, strength outcomes were not affected.

Moreover, Wilkinson and colleagues [ 94 ] demonstrated that ingestion of fat-free milk vs. soy or carbohydrate led to a greater area under the curve for net balance of protein and that the fractional synthesis rate of muscle protein was greatest after milk ingestion.

In , Reidy et al. However, when the entire four-hour measurement period was considered, no difference in MPS rates were found. A follow-up publication from the same clinical trial also reported that ingestion of the protein blend resulted in a positive and prolonged amino acid balance when compared to ingestion of whey protein alone, while post-exercise rates of myofibrillar protein synthesis were similar between the two conditions [ ].

Reidy et al. No differences were found between whey and the whey and soy blend. Some valid criteria exist to compare protein sources and provide an objective method of how to include them in a diet. As previously mentioned, common means of assessing protein quality include Biological Value, Protein Efficiency Ratio, PDCAAS and IAAO.

The derivation of each technique is different with all having distinct advantages and disadvantages. For nearly all populations, ideal methods should be linked to the capacity of the protein to positively affect protein balance in the short term, and facilitate increases and decreases in lean and fat-mass, respectively, over the long term.

To this point, dairy, egg, meat, and plant-based proteins have been discussed. As mentioned previously, initial research by Boirie and Dangin has highlighted the impact of protein digestion rate on net protein balance with the two milk proteins: whey and casein [ , , ]. Subsequent follow-up work has used this premise as a reference point for the digestion rates of other protein sources.

Using the criteria of leucine content, Norton and Wilson et al. Wheat and soy did not stimulate MPS above fasted levels, whereas egg and whey proteins significantly increased MPS rates, with MPS for whey protein being greater than egg protein. MPS responses were closely related to changes in plasma leucine and phosphorylation of 4E—BP1 and S6 K protein signaling molecules.

More importantly, following 2- and weeks of ingestion, it was demonstrated that the leucine content of the meals increased muscle mass and was inversely correlated with body fat. Tang et al.

These findings lead us to conclude that athletes should seek protein sources that are both fast-digesting and high in leucine content to maximally stimulate rates of MPS at rest and following training. Moreover, in consideration of the various additional attributes that high-quality protein sources deliver, it may be advantageous to consume a combination of higher quality protein sources dairy, egg, and meat sources.

Multiple protein sources are available for an athlete to consider, and each has their own advantages and disadvantages. Protein sources are commonly evaluated based upon the content of amino acids, particularly the EAAs, they provide.

Blends of protein sources might afford a favorable combination of key nutrients such as leucine, EAAs, bioactive peptides, and antioxidants, but more research is needed to determine their ideal composition. Nutrient density is defined as the amount of a particular nutrient carbohydrate, protein, fat, etc.

per unit of energy in a given food. In many situations, the commercial preparation method of foods can affect the actual nutrient density of the resulting food. When producing milk protein supplements, special preparations must be made to separate the protein sources from the lactose and fat calories in milk.

For example, the addition of acid to milk causes the casein to coagulate or collect at the bottom, while the whey is left on the top [ ]. These proteins are then filtered to increase their purity. Filtration methods differ, and there are both benefits and disadvantages to each. Ion exchange exposes a given protein source, such as whey, to hydrochloric acid and sodium hydroxide, thereby producing an electric charge on the proteins that can be used to separate them from lactose and fat [ ].

The advantage of this method is that it is relatively cheap and produces the highest protein concentration [ ]. The disadvantage is that ion exchange filtration typically denatures some of the valuable immune-boosting, anti-carcinogenic peptides found in whey [ ].

Cross-flow microfiltration, and ultra-micro filtration are based on the premise that the molecular weight of whey protein is greater than lactose, and use 1 and 0.

As a result, whey protein is trapped in the membranes but the lactose and other components pass through. The advantage is that these processes do not denature valuable proteins and peptides found in whey, so the protein itself is deemed to be of higher quality [ ].

The main disadvantage is that this filtration process is typically costlier than the ion exchange method. When consumed whole, proteins are digested through a series of steps beginning with homogenization by chewing, followed by partial digestion by pepsin in the stomach [ ]. Following this, a combination of peptides, proteins, and negligible amounts of single amino acids are released into the small intestine and from there are either partially hydrolyzed into oligopeptides, 2—8 amino acids in length or are fully hydrolyzed into individual amino acids [ ].

Absorption of individual amino acids and various small peptides di, tri, and tetra into the blood occurs inside the small intestine through separate transport mechanisms [ ]. Oftentimes, products contain proteins that have been pre-exposed to specific digestive enzymes causing hydrolysis of the proteins into di, tri, and tetrapeptides.

A plethora of studies have investigated the effects of the degree of protein fractionation or degree of hydrolysis on the absorption of amino acids and the subsequent hormonal response [ , , , , , ].

Further, the rate of absorption may lead to a more favorable anabolic hormonal environment [ , , ]. Calbet et al. Each of the nitrogen containing solutions contained 15 g of glucose and 30 g of protein.

Results indicated that peptide hydrolysates produced a faster increase in venous plasma amino acids compared to milk proteins. Further, the peptide hydrolysates produced peak plasma insulin levels that were two- and four-times greater than that evoked by the milk and glucose solutions, respectively, with a correlation of 0.

In a more appropriate comparison, Morifuji et al. However, Calbet et al. The hydrolyzed casein, however, did result in a greater amino acid response than the nonhydrolyzed casein. Finally, both hydrolyzed groups resulted in greater gastric secretions, as well as greater plasma increases, in glucose-dependent insulinotropic polypeptides [ ].

Buckley and colleagues [ ] found that a ~ 30 g dose of a hydrolyzed whey protein isolate resulted in a more rapid recovery of muscle force-generating capacity following eccentric exercise, compared with a flavored water placebo or a non-hydrolyzed form of the same whey protein isolate.

In agreement with these findings, Cooke et al. Three and seven days after completing the damaging exercise bout, maximal strength levels were higher in the hydrolyzed whey protein group compared to carbohydrate supplementation.

Additionally, blood concentrations of muscle damage markers tended to be lower when four ~g doses of a hydrolyzed whey protein isolate were ingested for two weeks following the damaging bout. Beyond influencing strength recovery after damaging exercise, other benefits of hydrolyzed proteins have been suggested.

For example, Morifuji et al. Furthermore, Lockwood et al. Results indicated that strength and lean body mass LBM increased equally in all groups.

However, fat mass decreased only in the hydrolyzed whey protein group. While more work needs to be completed to fully determine the potential impact of hydrolyzed proteins on strength and body composition changes, this initial study suggests that hydrolyzed whey may be efficacious for decreasing body fat.

Finally, Saunders et al. The authors reported that co-ingestion of a carbohydrate and protein hydrolysate improved time-trial performance late in the exercise protocol and significantly reduced soreness and markers of muscle damage.

Two excellent reviews on the topic of hydrolyzed proteins and their impact on performance and recovery have been published by Van Loon et al. The prevalence of digestive enzymes in sports nutrition products has increased during recent years with many products now containing a combination of proteases and lipases, with the addition of carbohydrates in plant proteins.

Proteases can hydrolyze proteins into various peptide configurations and potentially single amino acids. It appears that digestive enzyme capabilities and production decrease with age [ ], thus increasing the difficulty with which the body can break down and digest large meals.

Digestive enzymes could potentially work to promote optimal digestion by allowing up-regulation of various metabolic enzymes that may be needed to allow for efficient bodily operation. Further, digestive enzymes have been shown to minimize quality differences between varying protein sources [ ].

Individuals looking to increase plasma peak amino acid concentrations may benefit from hydrolyzed protein sources or protein supplemented with digestive enzymes. However, more work is needed before definitive conclusions can be drawn regarding the efficacy of digestive enzymes.

Despite a plethora of studies demonstrating safety, much concern still exists surrounding the clinical implications of consuming increased amounts of protein, particularly on renal and hepatic health.

The majority of these concerns stem from renal failure patients and educational dogma that has not been rewritten as evidence mounts to the contrary. Certainly, it is clear that people in renal failure benefit from protein-restricted diets [ ], but extending this pathophysiology to otherwise healthy exercise-trained individuals who are not clinically compromised is inappropriate.

Published reviews on this topic consistently report that an increased intake of protein by competitive athletes and active individuals provides no indication of hepato-renal harm or damage [ , ]. This is supported by a recent commentary [ ] which referenced recent reports from the World Health Organization [ ] where they indicated a lack of evidence linking a high protein diet to renal disease.

Likewise, the panel charged with establishing reference nutrient values for Australia and New Zealand also stated there was no published evidence that elevated intakes of protein exerted any negative impact on kidney function in athletes or in general [ ].

Recently, Antonio and colleagues published a series of original investigations that prescribed extremely high amounts of protein ~3. The first study in had resistance-trained individuals consume an extremely high protein diet 4.

A follow-up investigation [ ] required participants to ingest up to 3. Their next study employed a crossover study design in twelve healthy resistance-trained men in which each participant was tested before and after for body composition as well as blood-markers of health and performance [ ].

In one eight-week block, participants followed their normal habitual diet 2. No changes in body composition were reported, and importantly, no clinical side effects were observed throughout the study.

Finally, the same group of authors published a one-year crossover study [ ] in fourteen healthy resistance-trained men. This investigation showed that the chronic consumption of a high protein diet i. Furthermore, there were no alterations in clinical markers of metabolism and blood lipids.

Multiple review articles indicate that no controlled scientific evidence exists indicating that increased intakes of protein pose any health risks in healthy, exercising individuals. A series of controlled investigations spanning up to one year in duration utilizing protein intakes of up to 2.

In alignment with our previous position stand, it is the position of the International Society of Sports Nutrition that the majority of exercising individuals should consume at minimum approximately 1. The amount is dependent upon the mode and intensity of the exercise, the quality of the protein ingested, as well as the energy and carbohydrate status of the individual.

Concerns that protein intake within this range is unhealthy are unfounded in healthy, exercising individuals. An attempt should be made to consume whole foods that contain high-quality e. The timing of protein intake in the period encompassing the exercise session may offer several benefits including improved recovery and greater gains in lean body mass.

In addition, consuming protein pre-sleep has been shown to increase overnight MPS and next-morning metabolism acutely along with improvements in muscle size and strength over 12 weeks of resistance training.

Intact protein supplements, EAAs and leucine have been shown to be beneficial for the exercising individual by increasing the rates of MPS, decreasing muscle protein degradation, and possibly aiding in recovery from exercise.

In summary, increasing protein intake using whole foods as well as high-quality supplemental protein sources can improve the adaptive response to training. Campbell B, Kreider RB, Ziegenfuss T, La Bounty P, Roberts M, Burke D, et al. International society of sports nutrition position stand: protein and exercise.

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Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults. CAS PubMed PubMed Central Google Scholar. Tipton KD, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK, Petrini BE, et al. If it was clear-cut that if I, I don't know, lost X amount of skinfolds or gained X amount of muscles, increase my performance, that would definitely be the huge motivating factor.

I think its pretty important ed: body composition for me because I've seen how easy it is to move and to when you're in shape.

And I get told that a lot. Childhood upbringing was a major theme raised by the participants as a barrier to both body composition and healthy eating habits. Childhood barriers involved family size determined by the number of family members living in their house growing up , nutrition routine e.

I think we ate minimal. We weren't that well off, so we. So it was definitely—your food was definitely restricted. Oh, eggs, yeah, a lot of eggs, and cereal, yeah, one-off big barbecues, but yeah.

Mostly noodles was pretty good. Happy with that. Maybe every week ed: rely on others for food. Sometimes, I just have to have toast or something for dinner, so.

Childhood food routine was considered a determining factor in dietary habits that were carried into adulthood. I think, because I didn't really have much, having treats was like a I don't know—we didn't have it much, so when we, it would be hidden, and then when you'd get it, you'd be like, oh, happy as.

And so I think that's why now I eat so much because I can get it whenever I want. And like sometimes reaching for the wrong food.

But I suppose I've sort of broken the habit of continuously eating bad food. I don't reach for it as much. Um like But the tendency's still there, I suppose Player I always finish my plate.

Always, yeah Always eat my vegetables. Those who skipped breakfast and lunches during childhood were more likely to skip meals during adulthood. For example, one player who reported that they did not consume breakfast everyday in response to questioning about habits from childhood which still exist….

Not really eating breakfast. Not wasting food. The skipping of meals can lead to missed opportunities for nutrition intake as well as increased risk of bingeing at later meals. Time was an emerging theme as a barrier for athletes in eating an appropriate diet and is strongly linked to other barriers such as food security and cost.

The participant group of thirty Rugby Union players competing at an elite level, typically trained up to 30 h plus per week in addition to balancing study, work and family commitments. I think just probably just not being actually I don't know. Yeah, I think unmotivation or just time management.

Just sort of, when I can eat really, and because of work and stuff at the moment and then sort of money wise. Participant's in the current study report barriers to optimal nutritional intake which could be classed as either sport specific or general themes; childhood, body composition, nutrition knowledge, time management and food security, which is in line with previous research studies in athletes Heaney, ; Birkenhead and Slater, ; Stokes et al.

Highlighting that factors aside from nutritional needs should be considered when providing information to athletes. The influence of childhood upbringing as both a barrier and enhancer to dietary habits is interesting and shows the need for greater nutritional support at the developmental level.

This aligns with previous research which also suggests that upbringing can influence current eating habits Lake and Townshead, It would seem prudent to include family and whanau into any nutritional education which is provided to development players, especially as previous research into childhood nutritional intakes has shown parents and family members are influencers to healthy eating Birch et al.

Foods which are affordable must be included in any education program for players at all levels, especially where players are not full time professionals.

Similar statements about financial factors governing current food choices were also seen amongst non-super rugby players. However, education can only go so far and if there is insufficient money to buy food then nutrition knowledge will have limited benefit.

Access to healthy food and the increasing cost of healthy food is well-recognised among professionals as a barrier to optimal nutritional intake Heaney, Elite athletes on a limited budget report that financial constraints interfere with making food choices that support a healthy diet Heaney, In the current study, food costs in childhood and adulthood were barriers to optimal nutritional intake.

Food cost has been reported as influencing dietary intakes in male collegiate football players Long et al. Club provisions of snacks and meals or supermarket sponsorship could be strategies to promote desired dietary intakes.

However, providing food for the player without provision for the whanau family , is unlikely to solve the issue as players will likely share the food meaning provision is still sub-optimal. The issue probably needs a wider scope including public health policy around food insecurity of the population.

For example, the provision of meals in schools could potentially aid with food provision of developing players but the wider community, as well as serve as an opportunity for nutrition education Oostindjer et al.

The impact of media on nutritional intakes in the current study demonstrated differences by playing level with media not influencing intakes amongst the Super Rugby players, who instead relied on the team nutritionist, whereas those at lower levels, provincial and developmental reported being influenced by media and team mates something which has previously been reported amongst adolescent rugby players Stokes et al.

Although nutritional support at levels below Super Rugby is likely limited by funding this finding does highlight a potential need for education regarding the evaluation of information seen online or heard via team mates to ensure nutritional requirements and consequently health and performance are not compromised.

If rugby players, before they gain a professional contract, do not have access to professional nutritional advice; they are potentially vulnerable to opinions and unsubstantiated claims via social media, which could impact their development as players and potentially harm their future careers.

The potential of social media to compromise health and performance is something which was also highlighted amongst adolescent rugby players by Stokes et al. Body composition was raised as both a barrier and enabler to optimal dietary intake.

These dietary behaviours appear to be related to a lack of organisation and planning of meals throughout the week, this does suggest that assisting players to become more organised about meal preparation or delivery of meals could be of benefit to ensuring body composition goals are attained.

Lack of time and convenience have been reported as factors in food choice for athletes Smart and Bisogni, ; Heaney, ; Long et al.

Lack of meal planning and daily food shopping could increase the likelihood of consuming high fat high sugar processed foods, as in the general population meal planning has been associated with a healthier diet and lower levels of obesity Ducrot et al.

Time spent training and the weekly competition schedule mean that athletes have a lack of time to purchase, prepare and manage their dietary choices Long et al.

Athletes value foods that are convenient and easy to prepare. Often this leads to athletes purchasing convenience foods, which are typically unhealthy and not optimal for athletes Birkenhead and Slater, This was more commonly seen amongst developmental players who were also working or studying alongside training in order to support themselves and families.

This indicates the need for nutritional time management education, including quick cooks, healthy takeaway choices and meal prepping within sporting environments.

Experienced professional players from similar backgrounds to the developmental players e. This may help younger players with their dietary choices by providing advice on negotiating the barriers to optimal dietary intakes, such as organisational skills and importance of nutrition for performance and the use of social media.

Although the selection and training of the mentor would be important to ensure the advice provided will be of benefit to the mentee. Body composition was also an enabler for optimising dietary intakes through its influence on performance.

Participants identified body composition as an enabler to optimise nutrition strategies in order to reach body composition goals and therefore perform at a higher level.

Similar findings have been reported in previous research whereby sports performance has been reported by athletes as a motivation to food choice Heaney, ; Stokes et al. Therefore, focusing on the performance benefits of food choices may enable players to make adequate dietary choices and could be built into education programs alongside weekly meal planning.

Despite the findings of the current research they must be interpreted with caution as the Super Rugby players all played for the same club, with access to a nutritionist. However, some of these players had previously played for other franchises. Furthermore, although the current study included players from a range of ethnicities and socio-demographic backgrounds further research should be conducted to further investigate these potential influencers.

Investigations into the influences on dietary intakes of female rugby players should also be undertaken to aid the delivery of nutritional education to this group of players. Conducting individual interviews could be seen as a strength of the study as it removes any potential peer-pressure with responses, however, the study does rely on the assumption participants responded honestly.

This study uniquely describes the influences on dietary intakes amongst elite Rugby Union player's. It highlights that nutritional interventions require consideration of many social and economic factors which influence players' ability to adhere to any dietary intervention.

For example, organisational skills appear to be associated with maintenance of body composition and could be a non-nutrition skill that may help athletes adhere to dietary advice. Finally, social media influences dietary intakes more amongst developmental rugby players than super rugby players, thus educating players early about interpreting such information is recommended.

The datasets presented in this article are not readily available due to the nature of this research, participants of this study did not agree for their data to be shared publicly, so supporting data is not available.

Requests to access the datasets should be directed to the corresponding author. The studies involving human participants were reviewed and approved by the University of Otago Human Ethics and the University of Stirling Ethics Committees.

DB and KB were responsible for the study design, data collection, data analysis, and critically reviewing the manuscript. AS was involved with data collection and undertook data collection and analysed the data as well as drafting the manuscript.

SG and BS were involved with study design, data analysis, and critically reviewing the manuscript. All authors approved the final version of the paper. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers.

Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. Beck, K. Role of nutrition in performance enhancement and postexercise recovery. Open Access J. For athletes interested in increasing lean mass or muscle protein synthesis, consumption of a high-quality protein source such as whey protein or milk containing around 20 to 25 g protein in close proximity to exercise for example, within the period immediately to 2 hours after exercise may be beneficial.

As a general approach to achieving optimal protein intakes, it is suggested to space out protein intake fairly evenly over the course of a day, for instance around 25 to 30 g protein every 3 to 5 hours, including as part of regular meals. There is currently a lack of evidence to show that protein supplements directly improve athletic performance.

Therefore, for most athletes, additional protein supplements are unlikely to improve sport performance. A well-planned diet will meet your vitamin and mineral needs. Supplements will only be of any benefit if your diet is inadequate or you have a diagnosed deficiency, such as an iron or calcium deficiency.

There is no evidence that extra doses of vitamins improve sporting performance. Nutritional supplements can be found in pill, tablet, capsule, powder or liquid form, and cover a broad range of products including:.

Before using supplements, you should consider what else you can do to improve your sporting performance — diet, training and lifestyle changes are all more proven and cost effective ways to improve your performance.

Relatively few supplements that claim performance benefits are supported by sound scientific evidence. Use of vitamin and mineral supplements is also potentially dangerous.

Supplements should not be taken without the advice of a qualified health professional. The ethical use of sports supplements is a personal choice by athletes, and it remains controversial.

If taking supplements, you are also at risk of committing an anti-doping rule violation no matter what level of sport you play.

Dehydration can impair athletic performance and, in extreme cases, may lead to collapse and even death. Drinking plenty of fluids before, during and after exercise is very important. Fluid intake is particularly important for events lasting more than 60 minutes, of high intensity or in warm conditions.

Water is a suitable drink, but sports drinks may be required, especially in endurance events or warm climates. Sports drinks contain some sodium, which helps absorption. While insufficient hydration is a problem for many athletes, excess hydration may also be potentially dangerous.

In rare cases, athletes might consume excessive amounts of fluids that dilute the blood too much, causing a low blood concentration of sodium.

This condition is called hyponatraemia, which can potentially lead to seizures, collapse, coma or even death if not treated appropriately. Consuming fluids at a level of to ml per hour of exercise might be a suitable starting point to avoid dehydration and hyponatraemia, although intake should ideally be customised to individual athletes, considering variable factors such as climate, sweat rates and tolerance.

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