Individualization of nutritional intervention is multifaceted, and is a field of constant research, but it generally depends on: a) energetic demands of the athlete's participating sport and the athlete's current bioenergetic status, b) the athlete's goal, c)the athlete's food preferences, and d)athlete's schedule. Given that "performance" is a relative term, the word "sports" is also context specific. The sport of basketball is played by basketball players, similarly, an office job can be considered as a sport participated by office workers (Fink & Mikesky, 2018, p. 4).
The purpose of proper nutrition is to provide the cells in the body the right fuel type for energy expenditure. Understanding the metabolic demands of the participating activity, while comparing it to the metabolic condition of an athlete can shed some light on the type of nutritional intervention required. Using the example above, basketball is quite a glycolytic sport, the athlete may require more carbohydrate intake to fuel the energy needed for anaerobic respiration (Melzer, 2011); whereas, an office job is more aerobic in nature and the required fuel source may largely depend on fat instead (Hulston, 2010). The transition point between aerobic to anaerobic respiration is highly dependent on individual metabolic status, having an understanding in biochemistry and physiology can help nutrition professionals be more dose and time-specific with the athlete’s macro- and micro-nutrient needs. This can help optimize their performance and build efficiency in their training and/or rehabilitation.
With the overwhelming concurrent effects of nutrition on metabolism and human physiology, finding an outcome measure to monitor nutritional intervention efficiency may be difficult. A metric that may shed some light relates to mitochondrial function, as it relates to the body’s efficiency in energy production during both aerobic and anaerobic needs (Dohlmann et al., 2018; Granata et al., 2018; Maclnnis, 2016), and other mutisystemic functioning (Gorman et al., 2016). However, assessing mitochondrial function requires tedious and sophisticated technology (Sivitz, 2010) and becomes impractical as a day to day monitoring strategy, and difficult for the nutritional professionals to utilize as a clinical outcome measure. Using resting heart rate may be both practical and reliable as a health indicator as it relates to “cardiovascular disease, cancer and all-cause mortality” (Aune et al., 2017). Although not as directly related to performance of an athlete as metabolic health, but the ease of measure of resting heart rate allows for better reliability. Weight can also be practically effective and act as an indirect measure on caloric or energy consumption (Patterson & Sears, 2017) and hence metabolic health, however, this may only shed light on athletes who are in a relatively poor physical shape but be irrelevant on athletes who are relatively healthy.
A proper nutritional intervention can only be individualized with respect to the athlete’s intended goal(s), food preferences, and his/her daily schedule. An increase in muscle mass versus improvement in endurance are different goals and warrant different nutritional strategies. Increasing muscle mass involves a higher demand in the anabolic pathway, hence increasing dietary omega-3 fatty acids (Smith, 2011) and protein following resistance training (Morton, 2017) for example can help increase protein synthesis, whereas aerobic capacity may be complemented with chocolate milk intake (Ferguson-Stegall et al., 2011). Marco- and micro-nutrients can be flexible when it comes to different dietary preferences as well, an athlete who is plant-based for example will not negatively affect athletic performance compared to omnivores (Craddock et al., 2016), and can fulfill their nutritional needs with proper tinkering of both food source and supplementation. More studies are coming out on the effects of different eating patterns such as intermittent fasting and alternate-day fasting, which provides professionals another creative way of planning a nutritional intervention to accommodate different life schedules. Studies demonstrate that a higher fat oxidation capacity is observed when aerobic exercise is done during a fasted state compared to a fed state (Vieira, 2016). Similarly, performance metrics in well-trained cyclists show no differences between high muscle glycogen levels versus low muscle glycogen levels (Hulston, 2010), which indicates body in a fasted state does not negatively impact aerobic performance. Being goal-oriented with an outcome measure that is easily attainable for opportunities of frequent feedback, as well as allowing for flexibility to accommodate athlete needs can pave the way for a successful adherence to nutritional interventions (Desroches et al., 2013).
Due to the heterogeneous nutrition response, it becomes particularly important for nutrition professionals to start with themselves, and exercise an outcome based intervention that involves, first, the utilization of proper metrics; then, the trial and errors of various dietary strategies. The difficulties and challenges can then be sympathized and respected by the professional when helping athletes. If your health or fitness professional is not considering these nuances when advising your dietary plan, talk to him/her, and let him/her know that you care.
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