Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients.
full text (93 pages) available here as PDF: http://www.jissn.com/content/pdf/1550-2783-7-7.pdf
Richard B. Kreider, Colin D. Wilborn, Lem Taylor, Bill Campbell, Anthony L. Almada, Rick Collins, Mathew Cooke, Conrad P. Earnest, Mike Greenwood, Douglas S. Kalman, Chad M. Kerksick, Susan M. Kleiner, Brian Leutholtz, Hector Lopez, Lonnie M. Lowery, Ron Mendel, Abbie Smith, Marie Spano, Robert Wildman, Darryn S. Willoughby, Tim N. Ziegenfuss, Jose Antonio. ISSN Exercise & sports nutrition review: research & Recommendations. J Int Soc Sports Nutr 2010, 7:7 doi: 10.1186/1550-2783-7-7
Professor Richard Kreider has put an enourmous effort on this study. Under his leadership over 500 original studies were estimated when putting together this review. What food should we eat to thrive as an athlete? What sports products, increase performance?
Nearly one hundred pages long, this publication provides a comprehensive overview of the following issues:
1) The definitional category of ergogenic aids and dietary supplements
2) How dietary supplements are legally regulated
3) How to evaluate the scientific merit of nutritional supplements
4) General nutritional strategies to optimize performance and enhance recovery
5) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement
Ergogenic aid is any training method, a mechanical instrument, nutritional counseling, a pharmacological method or a psychological tool that can improve an athlete’s performance. In this we’re find ways to improve the effectiveness and / or a variety of ways to increase the opportunities to return to exercise.
Nutritional supplements are legal and safety
Some sports organizations have banned the use of certain dietary supplements (eg prohormones, ephedrine and muscle growth-enhancing nutritional supplements). If a dietary supplement is specifically prohibited, then working in the area of sports nutrition professionals have to stay away from these substances and to actively work against their use.
Many dietary supplements are not for long-term use. The use of nutritional supplements to consider for should remain very well-informed of possible side effects. Assessing the safety of the nutritional supplement supports the search for potential side effects of scientific and medical literature.
The classification of food supplements
Dietary supplements may contain carbohydrate, protein, fat, minerals, vitamins, herbs, enzymes, metabolic products, and / or different plant extracts. Dietary supplements, performance can be categorized as follows:
I. Apparently Effective. Nutritional supplements that help meet the energy needs of the public and / or in respect of which the majority of studies show that they are effective and safe
II. Possibly Effective. Dietary supplements which require for further studies on how these dietary supplements may increase performance.
III. Too early to tell. Nutritional supplements which might be efficient in a reasonable theory, but their efficacy has been confirmed because of too little data.
IV. Probably ineffective. Dietary supplements which have been identified in studies to be ineffective.
General dietary guidelines for active people
Well-planned diet that will satisfy the energy needs and contain enough nutrients, it is the foundation, upon which a good workout program will be created. Surveys show that energy and macronutrient deficit may interfere with the athlete’s adaptation to training compared to athletes who comply with the energy necessary for a satisfactory diet.
Energy deficient diet during training may lead to loss of muscle mass loss and degradation, increased susceptibility for sickness and risk of overtraining. Good dietary guidance inclusion into the training program is one way to optimize the integration of training and prevent overtraining.
One of the first tasks of training and performance through the optimization of nutrition, is to ensure the athlete receiving enough energy to replace the energy deficit.
General fitness program that is being practiced (eg, 30-40 minutes exercise per day, 3 times a week), can typically meet the nutritional needs by following the “normal” diet (1800-2400 kcal / day, or about 25-35 kcal / kg / day, if a man weighing 50-80 kg), because their exercise calorie consumption is not very significant (200-400 kcal / session).
Medium-level athletes who train intensively for 2-3 hours a day, 5-6 times a week, or top-level athletes (3-6 hours of exercise per day, 1-2 times a day and 5-6 days per week), can consume 600-1200 calories or more per hour during exercise. Therefore, their energy needs could increase 50-80 kcal / kg / day (2500-8000 kcal / day of 50-100kg press an athlete). Top-level athletes may be heavy demand for energy during exercise to be enormous.
For athletes who train at high intensity, it is often very difficult to eat enough food to meet calorie consumption.
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Brouns F, Saris WH, Beckers E, Adlercreutz H et al. Metabolic changes “induced by sustained exhaustive cycling and diet manipulation. Int J Sports Med 10 (Suppl 1): S49-62, 1989
Brouns F, Saris WH, Stroecken J et al. Eating, drinking, and cycling. A controlled Tour de France simulation study, Part I. Int J Sports Med 10 (Suppl 1): S32-40, 1989
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1): S41-48, 1989
Energy deficient diet during training is the surest way to achieve weight loss, but the result are often unwanted: muscle mass loss and worse athletic performance.
For sports nutrition professionals, it is important to work with athletes in order to ensure sufficient energy supply. It sounds so simple, but powerful practice that is often accompanied appendage such as the decrease in appetite.
Nutritional counselor should be particularly carefully refuted from inside to react to a situation where an athlete has no appetite. Energy-bar use offers athletes a way to meet the daily energy needs during exercise, athletes should be provided otherwise in danger of being deficient in energy intake.
Energy intake is also important to ensure the training and performance optimization of nutrition, to help athletes eat enough carbohydrate, protein and fat.
Sports enthusiasts can typically satisfy the needs for macronutrients by following the “normal” diet (45-55% carbohydrate, ie 3-5 g / kg / day, 10-15% protein, ie 0,8-1,0 g / kg / day and 25-35% fat, ie 0.5-1.5 g / kg / day).
Intermediate and high performance athletes need higher amounts of protein and carbohydrate to satisfy their macronutrient needs. For example, the average level of the athletes, who train 2-3 hours a day and 5-6 times a week, generally require a 55-65% carbohydrate (5-8 g / kg / day) or 250-1200 g / day for 50-150 kg in the case of athletes. Carbohydrate is needed to fil up liver and muscle glycogen stores.
Studies have shown that elite athletes (practicing 3-6 hours a day and 1-2 times a day, 5-6 days a week) may require 8-10 g / day, carbohydrate (400-1500 g / day for 50-150 kg athlete) to meet the muscle glycogen stores.
The majority of carbohydrates should be from foods with low glycemic index (eg, vegetables, fruits, whole grain cereals). Since it is difficult to get as much carbohydrate a day when an athlete to practice intensively, many sports nutrition professionals recommend the use of carbohydrate containing drinks during exercise.
Protein requirements of athletes is controversial. For “normal” people recommended protein intake is 0,8-1,0 g / kg / day. This amount is also sufficient for ordinary fitness.
Studies have shown that athletes who train intensively double the number of recommendations (1.5-2.0 g / kg / day).
Lemon PW, Tarnopolsky MA, MacDougall JD, Atkinson SA. Protein Requirements and muscle mass / strength changes “During intensive training in novice bodybuilders. J Appl Physiol 73 (2): 767-775, 1992
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Chesley A, MacDougall JD, Tarnopolsky MA et al. Changes in human muscle protein synthesis on Resistance Exercise. J Appl Physiol 73 (4): 1383-1388, 1992
Too little protein intake slows down the recovery drills. Even older people can benefit from the higher than normal protein intake (1.0-1.2 g / kg / day). This slows down the sarcopenia, or old age-related muscle degeneration.
Intermediate athletes recommended quantity of protein is 1-1.5 g / kg / day (50-225 g / day 50-150 kg athlete). Top-level athletes need 1.5-2.0 g / kg / day of protein (75-300 g / day for 50-150 kg athlete).
Protein quality is very important, since all the proteins are not identical. There are differences in the availability of amino acids and peptides, which exhibit biological activity (alpha-lactalbumin, beta-lactoglobulin, glycomacropeptide, immunoglobulins, lactoperocsidases, lactoferrin was also shown, etc.).
Also the absorption of protein and metabolic activity are important factors.
Bucci L, Unlu L. Proteins and Amino Acid Supplements in Sports and Exercise. In: Driskell J, Wolinsky I, editors. Energy-Yielding Macronutrients and Energy Metabolism in Sports Nutrition. Boca Raton, FL: CRC Press, 2000. p. 191-212.
Protein absorption ratio should be taken into account, for example: casein and whey protein are absorbed at different speeds, which affects the whole body catabolism and anabolism.
Boirie Y, Dangin M, Gachon P et al. Slow and fast dietary Proteins differently modulate postprandial protein accretion. Proc Natl Acad Sci USA 94 (26): 14930-14935, 1997
Boirie Y, Beaufrere B, Ritz P. Energetic cost of protein turnover in Healthy Elderly Humans. Int J Obes relat Metab Disord 25 (5): 601-605, 2001
Boirie Y, Gachon P, Corny S et al. Acute postprandial changes “in leucine metabolism as assessed with an intrinsically Labeled milk protein. Am J Physiol 271 (6 Pt 1): E1083-1091, 1996
The athlete must therefore take into account that he eats a high-quality protein. The best protein sources include chicken, fish and egg protein (casein and whey protein). High quality protein supplements from the best sources are whey, casein, milk proteins, colostrum and egg protein.
Fat on the nutrition recommendations for athletes are consistent with or slightly larger than for normal people. Higher fat diets maintain testosterone production better than low-fat diet.
Dorgan JF, Judd JT, Longcope C et al. Effects of dietary fat and fiber is a plasma and urine androgens and estrogens in men: a controlled feeding study. Am J Clin Nutr 64 (6) :850-855, 1996
Hämäläinen EK, Adlercreutz H, Puska P, Pietinen P. Decrease of serum total and free testosterone During a low-fat diet highfibre. J Steroid Biochem 18 (3): 369-370, 1983
Reed MJ, Cheng RW, Simmonds M et al. Dietary Lipids: an Additional regulator of plasma levels when sex hormone binding of globuli. J Clin Endocrinol Metab 64 (5): 1083-1085, 1987
It is recommended for athletes to eat 30% of dietary fat during normal training season and up to 50% when training hard.
Venkatraman JT, Leddy, J, Pendergast D. Dietary fats and immune status in athletes: clinical implications “. Med Sci Sports Exerc 32 (7 Suppl): S389-395, 2000
For athletes who want to reduce body fat percentage, it is recommended of 0.5-1 g / kg / daily fat intake.
Eating and refueling
Studies have shown that the timing and composition of meals are important optimize performance, training adaptation and prevention of overtraining. Carbohydrate absorption and storage of muscle and liver glycogen takes about four hours. If an athlete to practice in the evening, breakfast is the most important meal in view of the liver and muscles glykogen levels.
When exercise lasts longer than an hour, an athlete should drink glucose and electrolytes containing fluids to maintain blood glucose levels and prevent the body from drying out.
Nieman DC, Fagoaga OR, DE Butterworth et al. Carbohydrate supplementation affects blood granulocyte and monocyte trafficking vain Not Function on the 2.5 h of running. Am J Clin Nutr 66 (1): 153-159, 1997
Nieman DC. Influence of carbohydrate on the immune responses to intensive, prolonged Exercise. Exerc Immunol Rev 4:64-76, 1998
Nieman DC. Nutrition, exercise, and immune system function. Clin Sports Med 18 (3) :537-548, 1999
Burke LM. Nutritional Needs for Exercise in the heat. Comp Biochem Physiol A Mol Integra Physiol 128 (4): 735-748, 2001
Burke LM. Nutrition for post-exercise recovery. Aust J Sci Med Sport 29 (1): 3-10, 1997
Maughan RJ, Noakes TD. Fluid replacement and exercise stress. A brief review of studies is fluid replacement and some guidelines for the Athlete. Sports Med 12 (1): 16-31, 1991
After the session, an athlete must ensure that at least 30 minutes after that, he gets high quality carbohydrates (1 g / kg) and 0.5 g / kg protein. Carbohydrate containing meal should be consumed two hours after exercise. This nutritional practice has been exploited in most cases when you want to speed up the re-formation of glycogen and promote anabolism. This idea is supported following studies:
Zawadzki KM, Yaspelkis BB, 3rd, Ivy JL. Carbohydrate-protein complex increases the rate of muscle glycogen storage on Exercise. J Appl Physiol 72 (5): 1854-1859, 1992
Tarnopolsky MA, Bosman M, Macdonald JR et al. Post Exercise Protein-carbohydrate and carbohydrate Supplements Increase muscle glycogen in men and women. J Appl Physiol 83 (6): 1877-1883, 1997
Kraemer WJ, Volek JS, Bush et al AND. Responses to hormonal Consecutive days of heavy resistance Exercise with or without nutritional supplementation. J Appl Physiol 85 (4): 1544-1555, 1998