ERIN M. McCARTHY

Centre for Lifestyle Medicine Clinic at Northwestern Medical Faculty Foundation
675 North St. Clair, Suite 17-250, Chicago, IL 60611, USA

Abstract

This updated review provides a systematic, evidence-based analysis of nutrition and performance-specific literature with current scientific data related to energy needs, assessment of body composition, strategies for weight change, nutrient and fluid needs, and the role of the health care professional. Proper nutrition through food and fluids are key components to peak physical fitness. It has been increasingly recognized that nutrition interventions can allow athletes to train “smarter” rather than just training harder. Athletes need to consume enough energy to maintain appropriate weight and body composition while training for a particular sport or activity (1). Preparation strategies should include practicing competition strategies during each training phase, particularly the consumption of fluids and foods before, during and after exercise. A qualified sports dietitian, and in the United States, a Board Certified Specialist in Sports Dietetics (CSSD), should provide individualized nutrition direction and advice to a comprehensive nutrition assessment in athletes.
Proper nutrition supports training and can improve performance, whereas improper nutrition can be detrimental to performance. It has been increasingly recognized that nutrition interventions can allow athletes to train “smarter” rather than just training harder. A firm understanding of weight, body composition, sport-specific goals and expectations and long-term health is necessary when working with an athletic population. All of these factors are important to consider when determining energy, macronutrient, micronutrient and fluid needs. This comprehensive review incorporates a systematic, evidence-based analysis of nutrition and performance-specific literature with current scientific data related to sports nutrition and physical fitness.

ENERGY BALANCE

Meeting energy needs is a nutrition priority for athletes. Athletes need to consume adequate energy during periods of high-intensity and/or long-duration training to achieve appropriate body composition and maximize training effects. Low energy intakes can result in loss of muscle mass; menstrual dysfunction; loss of or failure to gain bone density; an increased risk of fatigue, injury, and illness; and a prolonged recovery (2).
Estimation of energy needs of athletes and active individuals can be achieved using a variety of methods. The Dietary Guidelines for Americans 2010 and the Dietary Reference Intakes (DRIs) (Table 1) provide energy recommendations for men and women who are slightly to very active (3, 4). The two prediction equations considered to most accurately estimate energy expenditure are the Cunningham equation (5) and the Harris-Benedict equation (6). The Cunningham equation, due to its consideration of fat-free mass, is considered one of the better prediction equations for use with athletes (7). To estimate total energy expenditure, basal metabolic rate or resting metabolic rate is multiplied by an activity factor of ...