Energy metabolism is fuel for exercise and human movement. Energy metabolism means using the food consumed to store energy in the form of adenosine triphosphate (ATP). The ATP breakdown produces energy causing the muscle to contract. Metabolism means “to change” and includes anabolism (to build up), for example, the use of amino acids to make the proteins that provide muscle mass. Catabolism (break down) is also a process for metabolism, for example, breaking down glycogen (stored glucose) to pyruvic acid for ATP production. ATP is the only source of energy for muscle contraction, and enough ATP defines our ability to perform physical activity (Housh, Housh, & DeVries, 2016). In summary, the athlete’s diet should take into consideration the metabolic demands of the type of sport or exercise activity.
The availability of carbohydrates is essential to exercise capacity (pre-exercise muscle glycogen stores and the amount of carbohydrates ingested). A low carbohydrate diet leads to low muscle glycogen stores, poor exercise capacity, and fatigue. After muscle glycogen is depleted, the body relies on the metabolism of fat and amino acids (muscles) to produce ATP. However, the metabolism of fat to produce energy is slow, and exercise pace also slows because less ATP is produced. After glycogen depletion, it can take from 24 to 48 hours to fully restore glycogen levels. On the other hand, appropriate diet and exercise can improve muscle glycogen stores and maximize the oxidation of fat resulting in improved performance, decreased fat mass, and increased muscle mass (Abernethy et al., 2005).
In simple words, the athlete’s exercise capacity is determined by the amount of energy the muscle can produce and how fast this energy is made available to use. If the energy demands exceed the rate of energy production in the skeletal muscle, fatigue occurs. Or, I should say that whatever the athlete consumes will have a direct effect on performance. Athletes know that they should not eat junk food; however, it is not only about the quality of the macronutrients. The quantity and the percentage of carbohydrates, protein, and fat also vary depending on the intensity of your training and the periods of competition or noncompetition.
For example, you are competing many times during the day. Suddenly, you feel demotivated, anxious, shaking, and fearful with many negative thoughts popping up on your mind. Then you compete again and lose; now you blame your mental game. However, it may not have anything to do with your mental game, and all those signs happened because of energy depletion. Remember; states of our body also influence the states of our mind and both influence performance.
Appropriate nutrition is essential for high performance and athletes who also consult with a certified professional in athletic nutrition can improve performance. It is not about reading about the latest diet on the internet, and there are many such as vegetarian, vegan, paleo, gluten-free, and others. Athletes can follow whatever nutritional trend they want to follow, but athletes must be sure that they are ingesting the proper amount of nutrients for their physical activity.
Abernethy, B., Hanrahan, S. J., Kippers, V., Mackinnon, L. T., Pandy, M. G. (2005). The biophysical foundations of human movement. Champaign, IL: Human Kinetics.
Housh, T., Housh, D. & DeVries, H. (2016). Applied exercise & sport physiology with labs. (4th ed). Scottsdale, Arizona: Holcomb Hathaway, Publishers.