Current issues in sports nutrition in athletes

Annotation: The benefits of sports nutrition evaluation and counseling are important to both elite athletes and active men and women of all ages who want to optimize health and performance. Proper nutrition is essential to staying metabolically healthy during a run, a draining practice, or as a year-round philosophy to perform maximally and to avoid or recover from injury. Major issues related to nutrition in sports include weight control, body composition, carbohydrate loading, hydration, eating disorders, and supplementation, to name a few. General sports nutrition guidelines and sports-specific concerns are reviewed.

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Sports nutrition encompasses several subjects including the energy, nutrient and fluid needs of athletes, assessment of body composition, strategies for weight change, special nutrient needs during training, competition, and recovery, and the use of supplements and nutritional ergogenic aids.

Active people require more energy to maintain lean tissue mass, for immune and reproductive function, and optimum athletic performance. Meeting calorie needs can be difficult for some athletes, especially in those sports where severe weight-loss practice and restricted intakes are common. When energy intake is limited, the body uses fat and lean tissues for energy, thus resulting in loss of strength and performance. Chronic undernutrition also places the athlete at risk for micronutrient deficiency. While there are recommended dietary allowances and activity factors for calculating calorie needs, the best indication that energy needs are being met is the athlete demonstrating maintenance of weight and body composition while training for a sport.

Protein, Carbohydrate, and Fat Needs in Athletes

Protein requirements are increased in athletes. Endurance athletes need 1.2 to 1.4 g/kg body mass per day. Resistance and strength-trained athletes need 1.6 to 1.7 g/kg body mass per day. This is compared with 0.8 to 1.0 g/kg body mass for nonathletes. For example, a 200-pound long distance runner would require approximately 118 g protein, while a 200-pound football player would need roughly 150 g. The nonathlete would only require about 75 g protein per day. (See Table for amount in protein found in food.)

Carbohydrate needs vary in athletes depending on overall energy needs, type of sport, and the sex of the athlete. Recommendations range from 6 to 10 g/kg body mass per day with the goals being maintenance of blood-glucose levels during exercise, and to replace muscle glycogen. In fact, replacing muscle glycogen is crucial for recovery from one training session to the next to maximize training gains. It is important to have nutritious carbohydrate snacks on hand immediately after training to initiate the re-fueling process. The following snacks are examples that provide sufficient carbohydrate to optimize recovery:

Male athlete (target 60-80 g carbohydrate).

* One 8-oz carton fruit yogurt + cereal bar + 8 oz of fruit juice

* 8 oz milk + cereal bar + 1 banana

* 32 oz sports drink

Female athlete (target 40-50 g carbohydrate).

* One 8 oz carton fruit yogurt + cereal bar or 1 banana

* 8oz milk + cereal bar

* 24 oz sports drink

Fat intake should also correspond with overall energy needs, with fat making up 20 to...