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Protein Consumption and Hydration in Competitive High School Students

Sabina Fidai Mackenzie Gavin Joseph D'Angelo Catherine Redler [email protected]


Physical activity and exercise training can lead to nutrition-related health issues in high school-athletes. A lack of knowledge by students and their coaches can greatly influence these health issues. There is an added pressure among male athletes to gain muscle mass, and the preconceived notion is that adding more protein to their diet will help them gain muscle. In an attempt to transition body fat into muscle, high school athletes are restricting calories to gain optimal results in body composition, and in turn increase performance. Contrary to belief, less protein is needed in order to lose weight (Helms, et al., 2014). Our body’s natural response to fewer calories is an increase in efficiency, similar to when our bodies are in starvation mode. According to Helms et al. (2014), less protein is needed during weight loss when the anabolic response to protein is enhanced, which is considered a negative energy balance. Student athletes and coaches need to be properly informed of the necessary balance between caloric intake, protein consumption, and the long-term effects this balance has on an athlete’s body.


What is better for you than protein? Proteins are the building blocks of every single cell within our bodies. The functions of proteins are vast and range from providing cellular structure, to regulating tissue and organ function. But how much protein do we really need, and can you really have too much? According to the Institute of Medicine’s Dietary Reference Intakes, the Recommended Dietary Allowance (RDA) of protein for both men and women is 0.8 grams of protein per kilogram of body weight per day. While some argue that in the presence of healthy kidney function, increased protein intake has no deleterious effects there is no significant evidence showing detrimental effects of a high protein diet on kidney function in healthy individuals (Martin, Armstrong, & Rodriguez, 2005). Poortmans & Dellalieux (2000) also showed that protein intake under 2.8 grams/kg/day did not impair renal function. Other studies report that high protein diets have a negative effect on kidney function (Schwingshackl & Hoffmann, 2014). However, both sides agree, that in the presence of impaired kidney functions, dietary protein should be restricted (Martin, Armstrong, & Rodriguez, 2005).

As outlined by the Institute of Medicine’s Dietary Reference Intakes, both men and women only need 0.8 grams per kilogram of body weight each day. While increased protein intake alone may cause no harm in a healthy adult, when in combination with other diet and exercise modifications, damage may be done. A major modification with significant health risks is dehydration (Brito, Roas, Brito, Marins, Córdova, & Franchini, 2012). Aimed at reducing total body weight, dehydration may be accomplished through the use of diuretic and laxatives, as well as training or exercising in high heat, or by the use of plastic clothing to promote excessive sweating. These actions may quickly disrupt fluid and electrolyte balances within the body. Additionally, dehydration can cause a significant decrease of blood flow to the kidneys.

Among competitive athletes, increased protein consumption in addition to other modifications to diet and exercise, is extremely common. There is a high prevalence of this among high school student-athletes (Couture et al., 2015). These methods used by student-athletes have the potential to cause serious health problems and even death.


Our kidneys act as filters for waste products. They also regulate fluid-electrolyte and acid-base balances. During times of significant dehydration, hypovolemia, or decreased fluid volume, may occur. In a hypovolemic state, perfusion to vital organs, specifically of the kidneys, can lead to decreased kidney function. Reduced kidney perfusion is the most common cause of Acute Kidney Injuries (AKI) (Ignatavicius & Workman, 2015). As kidney function declines, so does its ability to filter and remove waste products. As proteins are metabolized, or broken down, they release nitrogenous waste products. In a healthy individual with properly functioning kidneys, these waste products are excreted as urea. However, with impaired kidney function nitrogenous waste products are retained and can rise to toxic levels in the blood (azotemia). Dehydration with impaired kidney function can also cause fluid-electrolyte disturbances. An increase or decrease of any electrolyte level out of the normal range can lead to serious health issues, including death (Ignatavicius & Workman, 2015).


Our bodies work best when fluid and electrolyte balances are maintained within a narrow normal range. Water and electrolytes are the most important elements in our bodies. Any change in water or electrolytes outside of the normal range can affect the functioning of any and all cells, tissues and organs. The kidneys are crucial in helping to maintain this balance of fluid and electrolytes, and when the balanced is disturbed are the first to compensate. Hormones such as aldosterone and antidiuretic hormone (ADH) act directly on the kidneys to help preserve or eliminate fluid and electrolytes, as needed. During times of dehydration, aldosterone signals the kidney to reabsorb both sodium and water to maintain homeostasis. Likewise, ADH acts directly on the tubules of the kidneys to promote water reabsorption. The kidneys can even release their own hormone, renin, when blood volume is decreased, to maintain adequate tissue perfusion (Ignatavicius & Workman, 2015).

Dehydration alone can cause fluid-electrolyte imbalance. Also, it can cause decreased kidney function and damages. The damage to the kidneys further hinders the body’s ability to maintain fluid-electrolyte balance and the removal of other waste products. When kidneys cannot excrete excessive hydrogen ions acidity builds up causing the body to compensate by increasing respiratory action in order to keep blood pH normal. This increase in respiratory rate allows the excess build-up of carbon dioxide, or acidity, to be released through the lungs (Ignatavicius & Workman, 2015).

Electrolyte Imbalances

These electrolyte imbalances may occur as a direct result of dehydration or the effects of using laxative and or diuretics. Hypernatremia, or high sodium level can be caused by dehydration. As sodium continues to rise, the excess sodium pulls water out of surrounding cells, causing them to shrink. The now dehydrated, shrunken cells may no longer be able to function properly. Changes that may occur as a result include agitation, confusion, weakening of muscles, and decreased contractility of the heart (Ignatavicius & Workman, 2015). The kidneys manage potassium excretion, and when they are not functioning properly your body is at risk for hyperkalemia, which is a serious condition that can lead to cardiac changes (Ignatavicius & Workman, 2015). Similarly, when the kidneys are damaged your body does not produce adequate urine and the excretion of sodium is reduced leading to hypernatremia. Because water follows salt due to osmosis, hypernatremia can cause fluid retention and edema, which can lead to hypertension and cardiac disruptions (Ignatavicius & Workman, 2015). The body will not be able to produce red blood cells when uremia, iron and folic acid are deficient, which is the case in the later stages of kidney damage and anemia. Fluid and electrolytes must be balanced in order for the body to function properly, and when this delicate balance is disturbed it can lead to cardiac, hematological, and gastrointestinal changes.

Real-Life Application

Many high school student-athletes are under extreme pressure to perform well and excel at their sport. In the case of competitive combat, wrestling for example, athletes compete based on their weight class. Ideally, athletes are best served when they are as strong as possible while weighing as little as possible. These athletes often go the route of rapid-weight-loss, or a 5% decrease in total body mass in less than 1 week (Brito, et al., 2012). Rapid weight loss is often achieved through dehydration by means of laxatives, diuretics, and exercising or training in extreme heat or with plastic or restrictive clothing. In addition to these potentially life-threatening physical complications, dehydration can put individuals at great risk for injury during competition. Although the effects of rapid weight loss may not be evident at first, the stress the body undergoes to compensate for the loss of hydration can be harmful.

Similarly, Mettler, Mitchell, and Tipton (2010) conducted a short two-week research that found athletes who consumed an increased amount of protein were able to lose the same amount of body fat as athletes who consumed normal protein values. However, the athletes who consumed an increased amount of protein were able to reduce the amount of lean body mass, that was lost, whereas the control group lost more of their lean body mass. The amount of lean body mass lost by the athletes who increased their protein consumption was only 20% of the control group (Mettler, Mitchell, & Tipton, 2010). For athletes, losing lean body mass, which is considered to be the weight on the body that is not fat, is not their target goal. At the end of the study, the researchers concluded that as increase in protein consumption was beneficial in order to lose weight in a short amount of time, however, the long term effects of increased protein consumption can lead to decreased performance capabilities (Mettler, Mitchell, & Tipton, 2010).

Knowledge Gap

A study performed by Couture, et al. (2015), showed a significant gap in knowledge pertaining to proper nutrition when it comes to high school athletics. The study consisted of a four-part questionnaire reviewed by two dieticians specializing in sports nutrition. A questionnaire was given to high school coaches to fill out. The average score for nutrition-based knowledge among the high school coaches was 68.4%. Additionally, only 30% of coaches were able to correctly answer general nutrition questions. The results reported by this study are quite profound. High school coaches should serve as resources for young athletes, and this obvious gap may be a major issue causing health issues in this population (Couture, et al., 2015).

In a study done by Laurenson & Dubé in 2014, when active males ingested a carbohydrate and protein beverage, performance was not improved. On the contrary, there was an increase to their blood glucose levels. Ten male athletes were tested in two bouts of exercise consisting of a set routine with repetition. In one trial, athletes consumed a carbohydrate and protein beverage and in another study, a non-caloric placebo was ingested. The same amount of work out sets was performed in both trials and power was measured during the final set of each exercise. Results proved that overall performance between the subjects that ingested the carbohydrate and protein beverage was no different than the athletes that received the placebo. The study did find that in active males that ingested the carbohydrate ad protein beverage during exercise only had an increase in bench press performance, and an increase in blood glucose (Laurenson & Dubé, 2014). There is a significant gap in the knowledge regarding the short-term and long-term effects increased protein consumption has on overall athletic performance among high school athletes.


High school athletes undergo a vigorous and extensive training process in order to excel in the sport of their choice. Their bodies are pushed beyond their limits and modified continuously. By increasing protein in the diet and decreasing water consumption, athletes are causing serious long-term effects to their bodies. The risks associated with these diet modifications are not apparent immediately, however, educating athletes can decrease the life-long risks. In order to ensure these athletes are safe, coaches need to be well versed in providing proper nutritional advice to their athletes. Nonetheless, further research is necessary in order to properly understand the nutritional needs of a high school athlete.


Brito, C., Roas, A., Brito, I., Marins, J., Córdova, C., & Franchini, E. (2012). Methods of Body-Mass Reduction by Combat Sport Athletes. International Journal Of Sport Nutrition And Exercise Metabolism, 22(2), 89-97.
Couture, S., Lamarche, B., Morissette, E., Provencher, V., Valois, P., Goulet, C., & Drapeau, V. (2015). Evaluation of Sports Nutrition Knowledge and Recommendations among High School Coaches. International Journal Of Sport Nutrition And Exercise Metabolism, 25(4), 326-334.
Helms, Eric R., Zinn, Caryn, Rowlands, David S., & Brown Scott R. (2014). A Systematic Review of Dietary Protein During Caloric Restriction in Trained Lean Athletes: A Case of Higher Intakes. International Journal of Sport Nutrition and Exercise Metabolism. 24, 127-138.
Ignatavicius, D., & Workman, M. (2015). Medical-Surgical Nursing. Philadelphia: Elsevier Saunders.
Laurenson, D.M., & Dubé, D. J. (2014). Effects of carbohydrate and protein supplementation during resistance exercise on respiratory exchange ratio, blood glucose, and performance. US National Library of Medecine National Institues of Health. 2(1):1-5.
Martin, W., Armstrong, L., & Rodriguez, N. (2005). Dietary protein intake and renal function. Nutrition & Metabolism. Retrieved 12 November 2017, from
Mettler, S., Mitchell, N., & Tipton, K. (2010). Increased Protein Intake Reduces Lean Body Mass Loss during Weight Loss in Athletes. Medicine & Science In Sports & Exercise, 42(2), 326-337.
Schwingshackl, L., & Hoffmann, G. (2014). Comparison of High vs. Normal/Low Protein Diets on Renal Function in Subjects without Chronic Kidney Disease: A Systematic Review and Meta-Analysis. Plos ONE, 9(5), e97656.

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