The Balance of Macronutrients in Sports Nutrition

Cardiovascular, Food as Medicine, General Heatlh, Nutrient Deficiency

Wednesday, 15 January 2025

The Balance of Macronutrients in Sports Nutrition

Triathletes and other endurance athletes face unique physiological demands that necessitate a well-balanced intake of macronutrients and micronutrients. From generating adenosine triphosphate (ATP) to replenishing glycogen stores, a structured nutritional strategy is critical for optimizing performance, preventing fatigue, and aiding recovery. As a naturopath, understanding these principles allows us to guide athletes toward evidence-based dietary habits that align with their training and competition goals.

Macronutrients in Sports Nutrition

Protein: Protein plays a vital role during endurance activities, contributing 2-8% of energy requirements. It supports muscle repair, immune function, and recovery. Athletes should aim for 1.2-2.0 g/kg of body weight per day. For example, an 80 kg triathlete would require 96-160 g of protein daily, sourced from fish, poultry, eggs, dairy, legumes, and nuts. Adequate protein intake ensures muscle protein synthesis (MPS) and minimizes muscle protein breakdown (MPB).

Carbohydrates (CHO): Carbohydrates are the primary energy source for endurance exercise, stored as glycogen in muscles and the liver. Athletes should consume 5-12 g/kg/day, depending on their training intensity. For instance, a 70 kg athlete might need 350-840 g daily. Carbohydrate loading before a triathlon can super-saturate glycogen stores, postponing fatigue and enhancing endurance. Sources include whole grains, fruits, and starchy vegetables.

Fats: Dietary fats, particularly polyunsaturated and monounsaturated fats, are crucial for sustained energy and overall health. Fat stores provide a virtually unlimited energy reserve, supplying over 300,000 kJ during prolonged activities. Athletes should derive 20-35% of their total caloric intake from fats, focusing on sources like avocados, nuts, seeds, and oily fish. Intakes below 20% may compromise nutrient balance and energy availability.

Key Micronutrients for Athletes

Calcium: Calcium is essential for bone health and muscular contraction. Endurance training can strain the bones of the legs and feet, making adequate intake crucial. Athletes should meet the RDI of 1000 mg/day through leafy greens, dairy products, soy-based foods, and almonds.

Iron: Iron supports oxygen transport and energy production. Female athletes, in particular, are at higher risk of deficiency due to menstrual losses. The RDI is 8 mg/day for men and 18 mg/day for women, achievable through lean meats, legumes, and dark green vegetables.

Choline: Choline aids in neurotransmitter synthesis, lipid metabolism, and cell membrane integrity. Physically demanding exercise may increase its requirement. Athletes should consume 550 mg/day (men) or 425 mg/day (women) from eggs, meat, and almonds.

Hydration

Hydration is crucial for maintaining plasma volume, thermoregulation, and cardiovascular efficiency. Athletes lose significant fluid through sweat and evaporation during exercise. It is recommended to:

Drink 400-600 ml of water 2 hours before exercise.
Consume 100 ml every 10 minutes during activity.
Replace lost fluids post-exercise to restore optimal hydration levels.

Dehydration can lead to hypo-hydration and hyperthermia, significantly impairing performance and increasing health risks. Monitoring body weight pre- and post-exercise is an effective way to assess fluid losses.

Nutrient Timing

Nutrient timing refers to strategically consuming nutrients before, during, and after exercise to enhance performance and recovery. Key considerations include:

Pre-exercise: Consume 1-4 g/kg of carbohydrates 1-4 hours before activity, complemented by moderate protein and fluids.
During exercise: Intake 0.5-1.0 g/kg of carbohydrates per hour, along with electrolytes and water. Examples include sports drinks, fruit, and energy bars.
Post-exercise: Focus on the “Three R’s”:
- Refuel with carbohydrates to restore glycogen.
- Repair with protein for muscle recovery.
- Rehydrate with fluids and electrolytes.

Supplementation

Most athletes can meet their nutritional needs through a balanced diet. However, vitamin D supplementation may benefit those at risk of deficiency, given its role in calcium absorption, immune support, and cardiovascular health. Athletes with specific conditions, such as Type 1 diabetes, may benefit from tailored dietary interventions, such as the DASH or Mediterranean diets, to improve glycemic control and reduce cardiovascular risk.

Practical Tips for Triathlon Nutrition

Before the Event:

Test various foods and hydration strategies during training to identify what works best.
Consume a balanced meal rich in carbohydrates 3-4 hours before the race.
Hydrate adequately, aiming for 400-600 ml of water 2 hours prior.

During the Event:

Maintain hydration with small, frequent sips of water or electrolyte-rich drinks.
Replenish glycogen with easily digestible carbohydrate sources such as gels, bananas, or dried fruit.
Avoid dehydration by consuming 30-60 g of carbohydrates and 600 ml of fluids per hour.

Recovery:

Consume a meal or snack containing carbohydrates and protein within 30 minutes post-race to maximise glycogen synthesis and muscle repair.
Rehydrate to replenish fluid losses and restore electrolyte balance.

Conclusion

A well-planned balance of macronutrients, micronutrients, and hydration supports triathletes in achieving their peak performance. Incorporating nutrient timing and individualized dietary strategies ensures endurance, recovery, and overall health. Naturopaths can play a vital role in guiding athletes to make informed nutritional choices for long-term success.

References

Alaunyte, I., Stojceska, V., & Plunkett, A. (2015). Iron and the female athlete: a review of dietary treatment methods for improving iron status and exercise performance. Journal of the international society of sports nutrition, 12(1), 38. Retrieved from https://link.springer.com/article/10.1186/s12970-015-0099-2

Eat of Health (2020). Fat. https://www.eatforhealth.gov.au/food-essentials/fat-salt-sugars-and-alcohol/fat

Egan, B. (2016). Protein intake for athletes and active adults: Current concepts and controversies. Nutrition bulletin, 41(3), 202-213. Retrieved from https://onlinelibrary.wiley.com/doi/abs/10.1111/nbu.12215

Krzywański, J., Mikulski, T., Pokrywka, A., Młyńczak, M., Krysztofiak, H., Frączek, B., & Ziemba, A. (2020). Vitamin B12 Status and Optimal Range for Hemoglobin Formation in Elite Athletes. Nutrients, 12(4), 1038. Retrieved from https://laureate-au.blackboard.com/webapps/ blackboard/content/listContent.jsp?course_id=_94437_1&content_id=_9216665_1&mode=reset

Larson-Meyer, D. E., Woolf, K., & Burke, L. (2018). Assessment of nutrient status in athletes and the need for supplementation. International ournal of sport nutrition and exercise metabolism, 28(2), 139-158. Retrieved from https://www.researchgate.net/profile/Pedro_Teixeira23/ publication

Ley, S. H., Hamdy, O., Mohan, V., & Hu, F. B. (2014). Prevention and management of type 2 diabetes: dietary components and nutritional strategies.Lancet (London, England), 383(9933), 1999–2007. Retrieved from https://doi.org/10.1016/S0140-6736(14)60613-9

Penry, J. T., & Manore, M. M. (2008). Choline: an important micronutrient for maximal endurance-exercise performance?. International journal of sport nutrition and exercise metabolism, 18(2), 191-203. Retrieved from https://www.researchgate.net/profile/

Jager, R., Kerksick, C. M., Campbell, B. I., Cribb, P. J., Wells, S. D., Skwiat, T. M., Wilborn, C. D. (2017). International society of sports nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition, 14. Retrieved from https://doi.org/10.1186 s12970-017-0177-8

Nutrition Australia (2020). Diabetes. Retrieved from https://nutritionaustralia.org/fact-sheets/diabetes/

Nutrient Reference Valuse (2020). calcium. Retrieved from https://www.nrv.gov.au/nutrients/calcium

Nutrient Reference Valuse (2020). Iron. Retrieved from https://www.nrv.gov.au/nutrients/iron

Tarnopolsky, M. A., Gibala, M., Jeukendrup, A. E., & Phillips, S. M. (2005). Nutritional needs of elite endurance athletes. Part II: Dietary protein and the potential role of caffeine and creatine. European Journal of Sport Science, 5(2), 59-72. Retrieved from https://www.researchgate.net/profile/Stuart_Phillips/publication/271927558

Tarnopolsky, M., Gibala, M., Jeukendrup, A., & Phillips, S. (2005). Nutritional needs of elite endurance athletes. part i: carbohydrate and fluid requirements. European Journal of Sport Science, 5(1), 3–14. Retrieved from https://lesa.on.worldcat.org/atoztitles/link?

Sports dietitians Australia (2020). Retrieved https://www.sportsdietitians.com.au/wp-content/uploads/2015/04/Marathon_Fact_Sheet_web-ready.pdf

Volpe, S. L. (2007). Micronutrient requirements for athletes. Clinics in sports medicine, 26(1), 119-130. Retrieved from https:// www.researchgate.net/profile/Stella_Volpe/publication/6561012_Micronutrient_Requirements_for_Athletes/links/ 5cc4be22299bf1209784cd6c/Micronutrient-Requirements-for-Athletes.pdf