It is clear from the recent literature that total energy and macronutrient composition of the diet modulates acute exercise performance and adaptation to training. Since athletic activities demand high amount of energy, it is important to understand how energy is produced and how the demand for energy during athletics drives energy utilization. This understanding can be utilized and is critical to recommend appropriate dietary choices to replace that energy and refuel for the next bout of athletic activity (Bowman, B.A. and Russell, R.M., Eds., 2002).
Principles: The basic principles of energy transduction dictate that the flow of energy into the body must balance energy flow out of the body plus or minus energy storage. The human species is adapted to survive in the face of intermittent food availability; therefore, the efficient storage of food energy in periods of abundance is a metabolic priority. The form of energy that is utilized for performance of activity is adenosine triphosphate (ATP). ATP storage in the body is severely limited, therefore, there must be storage form of energy that can be rapidly activated and can respond to changes in energy demand at the time of athletic activity. ...
Objective of Nutritional Assessment: The basic concept in athletic nutrition is balance between energy expenditure and nutritional intake. From the above principles, it is clear that endurance athletes need protein, carbohydrates, and fluid in greater amounts. It also enumerates that the nutritional needs of the athletes must be sport-specific and individualized. While the concept of achieving energy balance is simple apparently from the thermodynamic perspective, the tools for measuring this entity are no ideal. This is specifically applicable to the estimation of energy intake that unless observed and quantified is usually left to the subjective recall of the athletes who are entrusted to remember, accurately estimate, and document their food intake using some record of diet. Even though, the athletes practice the most conscientious record, there are several limitations in such methods. To name a few, these are dietary constituent of interest; monitoring techniques, such as, 24-hour recall, food frequencies, and diet record; seasonal changes in training and eating; and natural limitations imposed by estimation techniques and subject compliance. Measurement of food intake may alter the dietary practice. Energy expenditure measurement can be very accurate when measured in a controlled laboratory by indirect calorimetry. Thus definitive assessment of energy balance and control can only reliably be afforded by measurement of fluctuations in body weight and body composition (National Research Council, 1989).
Anthropometry: The relationships between diet, athletic activity, and weight are closely linked. Ordinary factors, such as, training,