Today’s post is a bit different from what I normally would post about, but I think it’s really important to share the nutrition space with other passionate nutrition professionals. And while I wish I understood Sports Nutrition better, I understand it’s better to be a master of just a few skills, rather than all. Plus how fun is it to learn about other people’s specialties! Today’s contributor is JohnPaul Paganini, an MSc Human Nutrition student majoring in Sports Nutrition who aims to provide evidence-based nutritional advice upon graduation. You can check out his lifestyle blog: https://www.mypassionista.com or follow him on Twitter @jppaganini or Instagram @streetsdesirejohnpaul. I’ve also written an article on his blog about low-cost Spring gardens so please, head over to his site and show it some love. Contributors are also welcome on his blog!
Contrary to popular belief, carbohydrates and adequate carbohydrate fuelling is pivotal in sports and exercise. Sports persons and those actively engaged in sports competition ranging from Sunday league players through to elite performance and ultra-marathon athletes have specific nutritional requirements that need to be met from their diet to perform at a competitive level. Recommendations on macronutrient intake and hydration have been proposed by researchers with the aims of boosting sporting performance and assisting with pre, during and post event participation.
Leading the way in evidence-based dietary research and recommendations for sports persons in their specific sporting contexts – is the International Olympic Committee (IOC). The IOC has published several consensus statements (IOC, 1991), (IOC, 2003) (IOC, 2010) which underscore the importance of optimal diets for sports performance and to avoid injury and illness. Diets which reflect the training load and competition demands in terms of energy, carbohydrate (CHO), protein, fats and micronutrients will help competitors meet body size goals and body competition as well as perform when required to.
As part of the IOC’s work, a booklet was produced for athletes (IOC, 2003) with sports-specific dietary recommendations covering pre, during and post training and competition phases. Of relevance to this study are the recommendations contained around team sports and strength and power events given the nature of the sport the participant of this study is engaged in which is rugby.
Contrary to popularised thinking and the advent of low CHO / ketogenic dietary regimes, CHO adequacy in sports performance is a fundamental requirement. “During high-intensity training, particularly of long duration, athletes should aim to achieve carbohydrate intakes that meet the needs of their training programs and also adequately replace carbohydrate stores during recovery between training sessions and competitions”. (IOC, 2010 pp.1). This is even more important for events greater than one hour.
Table 1: Consensus statement summaries.
|IOC Year of release||Recommendation|
|IOC Consensus statement 1991||Focused on the effects of dietary manipulation on sports performance. CHO likely to contribute 60-70% of total energy, with protein 12%. Supplements unnecessary.|
|IOC Consensus statement 2003||Less prescriptive. Broader nutritional guidelines. Amount, composition and food timing affect sports performance. Athletes should aim to meet requirements of the sporting requirements and optimise restoration of muscle glycogen stores between workouts.|
|IOC Consensus statement 2010||Emphasis on pre, during and post-exercise nutrition for good mental and physical performance. Ingestion of small amounts of CHO during exercise can enhance cognitive and physical performance. Low energy availability should be avoided.|
Evolution of IOC Consensus statements
With regards to CHO, the competitor’s eating plan must provide enough CHO to optimise recovery of muscle glycogen (where CHO is stored as well as the liver) between exercise or competition bouts. For immediate recovery after exercise a recommended amount of 1g per kg of bodyweight per hour is recommended, perhaps at frequent intervals (IOC, 2003). CHO-rich foods with moderate GI provide optimal and available sources of CHO for glycogen synthesis. Some examples of carbohydrate-rich foods/meals include: breakfast cereals, most forms of rice, sports drinks, stir-fry with rice and noodles (IOC, 2003).
The notion of glycogen sufficiency and its cruciality when it comes to carbohydrate comes from the fact that training induced depletion of glycogen stores can lead to fatigue in athletes and impair performance (Jeukendrup & Williams, 2011, p32-41) by the production of lactic acid which contributes to a sense of fatigue and impaired muscle function and the familiar burning sensation.
The degradation of muscle glycogen occurs along two main metabolic pathways – ‘anaerobic’ and ‘aerobic metabolism’. Anaerobic metabolism is fulfilled by glycolysis which breaks down glucose into two modules of adenosine triphosphate (ATP) to provide energy in muscles for shorter duration, intermittent activity in the absence of oxygen and places a significant burden on glycogen stores.
Aerobic metabolism combusts CHO, amino acids and fats and requires the presence of oxygen and is more efficient at creating ATP – (yield 39 molecules of ATP versus 2 in anaerobic) and is more evident in activities of sustained effort such as running. It is effectively more energy producing. Aerobic metabolism enters the ‘Krebs cycle’ or ‘TCA cycle’ – a complex interaction of chemicals to produce exothermic energy from hydrogen ions (Appleton & Vanbergen, 2013). This leads to the notion of ‘energy availability’ – (Burke et al, 2011). This is defined as energy intake minus energy demand from exercise. Situations of poor energy availability, and poor availability of CHO as an energy source can cause immunological and bone mineral deficits as well as amenorrhea in female competitors.
For a typical sports person, regular or professional exerciser, the IOC recommendation for percentage of diet coming from carbohydrate sources is around 60% or 5-7g of CHO per kg of bodyweight for recovery from moderate duration or low intensity exercise. Endurance athletes or marathon runners require more; around 7-12g per kg of bodyweight for recovery from moderate-heavy endurance training. For immediate recovery after exercise (0-4 hours): about 1g per kg of bodyweight, perhaps consumed at frequent intervals.
For more personalised nutrition advice, you should book a session with a registered dietitian, registered (associate) nutritionist (AfN) or Sport & Exercise nutritionist (SENR).
Appleton, A. and Vanbergen, O. (2013) ‘Introduction to Metabolism’. Horton-Szar, D. amd Dominiczak, M.H (eds.) Metabolism and Nutrition. London: Mosby Elsevier. pp1-8.
Appleton, A. and Vanbergen, O. (2013) ‘Energy Metabolism II: ATP generation’. Horton-Szar, D. amd Dominiczak, M.H (eds.) Metabolism and Nutrition. London: Mosby Elsevier. pp17-21.
IOC (2003) Nutrition for Athletes: A Practical guide to eating for health and performance. Nutrition working group of the Medical Commission of the International Olympic Committee, Lausanne.
Jeukendrup, A. & Williams, C. (2011) ‘Carbohydrate’. Lanham, S.A. New, Steer, S.J., Shirreffs, S.M., and Collins, A.L. (eds.) Sport and Exercise Nutrition. Oxford: The Nutrition Society, Blackwell Publishing. pp32-41.
Maughan, R.J., Burke, L.M., and Coyle, E.F. (eds.) (2004) Foods, Nutrition and Sports Performance II. London: Routledge.
Maughan, Ron. J., and Shirreffs, S. (2010) IOC Consensus Conference on Nutrition in Sport, 25-27 October 2010, International Olympic Committee, Lausanne, Switzerland, Journal of Sports Sciences, 29:supl1, S1-S1. Doi: http://dx.doi.org/10.1080/02640414.2011.619399
Williams, C. and Delvin, J.R. (eds.) (1991) Foods, Nutrition and Sports Performance. An International Scientific Consensus organized by Mars Incorporated with International Olympic Committee patronage. London: Routledge.