Are you a nutrition professional wanting to learn more about sports nutrition?
Maybe you’re thinking of a career as a dietitian for athletes or sports performance nutritionist?
This article will give you the basic must know information about sports nutrition that you will need as a nutrition professional focusing on sports nutrition.
How to Become a Sports Dietitian? Start with knowing the basics of sports nutrition!
This content is based on our sports nutrition course created with support from Terence Boateng, RD, CSEP-CEP, MHSc. Learn even more about sports nutrition counseling, build your expertise, and get access to ready-to-use resources.
Sports Nutrition Basics
Having an understanding of sports nutrition, exercise physiology, and athlete energy requirements is essential to become a sports dietitian because:
- High-level athletes have different nutrition requirements than the general population
- A knowledge base around exercise physiology can empower nutrition professionals to aid in injury prevention
- Non-nutrition professionals like sports coaches and personal trainers tend to provide the bulk of nutrition recommendations
Exercise Physiology Basics
Basically, fueling requirements differ for athletes based on which energy-producing system is being activated:
These energy-producing systems are:
- Aerobic metabolism
- Anaerobic metabolism
- Phosphocreatine System
Firstly, aerobic metabolism is the body’s method of producing energy in the presence of oxygen (1). We primarily use this metabolism for activities of daily living, but the system can be ramped up during exercise.
Sports that predominantly rely on aerobic metabolism include:
- Long distance swimming
- Cross country skiing
So, the key feature of these sports is that they require a steady energy output over an extended period with little to no rest periods.
Secondly, anaerobic metabolism.
Do you ever feel an intense burn when lifting weights or doing a hard run? This is a sign that you’re in the anaerobic zone.
Sports that rely on predominantly anaerobic metabolism include:
- 400 meter dash
- Martial Arts
These are typically sports performed at high intensities for short periods of time, or sports with a lot of breaks available to the athletes.
Finally, the phosphocreatine system. We use this system for explosive movements that are very short-lived, like jumping, tackling and throwing (1), i.e.
- 100-meter dash
- High jump
- American Football
Nutrition & Intensity
So, how does intensity affect nutrition?
At a low intensity, the body uses mostly fat as a fuel source. This is because fat is abundant, as we store plenty throughout our body. As the exercise intensity increases, the body relies more and more on carbohydrates rather than fat. As one approaches near maximum exercise intensity, like in sprinting, the mix is nearly 100% carbohydrates, as the body is now relying on anaerobic glycolysis (1).
So why does this matter?
As a sports dietitian, understanding this relationship will drive your recommendations for pre-exercise nutrition planning.
Nutrition & Duration
Another key point is how the duration of an activity can affect the nutrients used (1). In general, the longer the activity, the more we rely on fat versus carbohydrates.
This helps to explain why we slow down as the duration extends. The reason more fat is used is simply that glycogen gets depleted over time, resulting in athletes needing to slow down and use fat.
As a dietitian for athletes, understanding how long an athlete needs to compete and at what intensity helps to customize nutrition recommendations.
So, now that we’ve covered how intensity and duration affect the mix of nutrients used during an activity, let’s discuss the specific carbohydrate, fat and protein recommendations.
Carbohydrates As a Fuel Source
Carbohydrates are very important for sports nutrition, because:
- Unlike fat and protein, carbohydrates have a very limited storage capacity in the body.
- Carbohydrates are the key fuel source for high-intensity activity but can also be used for low intensity.
- A lack of stored carbohydrates is linked to fatigue, impaired skill, and decreased concentration (2).
Endurance athletes (like marathon runners) may experience a situation known as “hitting the wall” if they haven’t fueled properly (3).
For most of the race, they feel great and can maintain a consistent pace. However, suddenly they experience:
- Rapid onset of severe fatigue
- Inability to maintain a high-intensity pace
Under those circumstances, glycogen stores are depleted and thus there is a lack of available glucose to fuel the fast pace. Endurance athletes avoid this by consuming carbohydrates before their event and consuming sports gels and sports drinks during the event.
How much carbohydrate is recommended for an athlete is dependent on the intensity and duration of the sport.
Fat as Fuel
Our body relies heavily on free fatty acids, intramuscular fat, and adipose tissue to fuel activity. Unlike carbohydrates, the body does not rely heavily on dietary fat to fuel performance directly.
So why is fat important?
For the same reasons fat is important for everyone, fat makes up cell membranes in addition to helping the body:
- Absorb fat-soluble vitamins
- Insulate the organs
- And a variety of other essential functions
Because carbohydrates and protein have a heavier emphasis in sports performance, some athletes who are trying to lose weight may restrict fat intake. This should be discouraged as it can lead to a host of essential fatty acid and vitamin deficiencies that negatively impact health. Athletes are recommended to consume 20-35% of their energy from fat (2).
Under most circumstances, very little dietary protein is used by our energy systems during activity. When protein is being used, it’s a sign that an athlete has not been adequately fueled with carbohydrates, and thus the body must try and convert protein into glucose. This is a highly inefficient process and could result in losses in muscle mass over time.
So why is protein important?
Protein allows for muscle repair after training which is critical to the body’s adapting and improvement. Athletes train more frequently and at higher intensities than the general population and therefore need more protein (4).
The general recommendations for protein are 1.2-2.0 g/kg/day for athletes (2).
Learn more about macronutrient requirements for sports:
We dive into each one of these in more detail in the DSC Sports Nutrition course with case studies to help you learn how to apply the information. You also get instant access to sports nutrition handouts and resources including
- Sports Supplements Evidence Guide
- Energy and Macronutrient Needs calculation cheat sheet
- and Pre and Post-Workout Fueling handout for clients
- To become a sports dietitian, you will need a knowledge base of exercise physiology to support athletes in meeting their unique nutritional requirements
- Different types of sports utilize different energy systems; aerobic, anaerobic, and phosphocreatine systems
- Duration and intensity of sport impacts the nutritional needs of athletes
- Carbohydrates are an important fuel source and insufficiency can lead to fatigue and impaired skill
- Athletes should not limit fat due to its importance in normal bodily functions
- Protein allows for muscular repair which is critical to athletic performance
Dietitian Success Center is THE professional development resource for dietitians and dietetic students. Our mission is to make it easier for dietitians and dietetic students to build expertise. We do this through evidence-based online nutrition courses, community and ready-to-use client handouts. Plus – we give you the tools to start and grow your dietitian private practice!
1. Victor L. Katch, William D. McArdle, and Frank I. Katch. (2011) Essentials of exercise physiology. Baltimore, MD: San Franciso, CA: Pearson education Inc, 2011) Page 317, 939-946, Date) Page 188
2. Thomas, D Travis et al. “Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance.” Journal of the Academy of Nutrition and Dietetics vol. 116,3 (2016): 501-528. doi:10.1016/j.jand.2015.12.006
3. Buman, MP, Brewer, BW, Cornelius, AE, Van Raalte, JL & Petitpas, AJ 2008, ‘Hitting the wall in the marathon: Phenomenological characteristics and associations with expectancy, gender, and running history’, Psychology of Sport and Exercise, vol. 9, no. 2, pp. 177-190. https://doi.org/10.1016/j.psychsport.2007.03.003
4. Kerksick, Chad et al. “International Society of Sports Nutrition position stand: nutrient timing.” Journal of the International Society of Sports Nutrition vol. 5 17. 3 Oct. 2008, doi:10.1186/1550-2783-5-17