By nutritionist James Morehen
All together 20 nations across the globe play in the Rugby World Cup, with each country taking 31 players to the tournament. We will see 620 international professional rugby players of all different shapes and sizes.
Considering the extensive range in lean mass, fat mass and total body mass in all these players, there really is no one set, pre-game diet to follow as a rugby player. In addition to body composition differences, some players struggle to eat due to lack of sleep, feeling nervous due to adrenaline increases or even unsure as to what to eat! Together, this is why nutritional requirements for rugby players must be tailored to each player.
The media has clearly highlighted the amount of pre-tournament games teams have played, and unfortunately for Wales the cost to some key players. However, the combined result of pre-tournament training camps and games paired with structured and smart nutrition will allow nations to arrive at their first game with athletes in the best physical and metal shapes of their lives, adopting low body fat and high lean mass and importantly with a practiced nutritional strategy ready for kick off.
The day before game day…
Typically, the most important day of the week is game day and how to arrive at kick off having fueled the body adequately. Currently, it is still unclear as to what the underlying mechanism behind a reduced exercise performance towards the end of a game is. However, one popular candidate is the attenuation of muscle glycogen leading to premature fatigue during prolonged intermittent exercise (Balsom et al., 1999). Granted, this work was performed in soccer and we know that soccer and rugby differ majorly. In particular, distances covered (Twist et al., 2014 & Bangsbo et al., 1994) match activities (Twist et al., 2014) and most notably anthropometric body composition profiles displaying large inter- and intra-positional variances in rugby (Morehen et al., 2015) when compared to soccer players who show a more homogenous profile (Iga et al., 2014).
Moving forward, if the candidate for fatigue is gradual reductions in muscle glycogen, what should we be eating in the days leading into a game?
First of its kind…
Recently, this has been an area of interest for a group of research colleagues and myself at Liverpool John Moores University. The aims for our research group was to asses the physiological metabolic demands of an 80-minute game under two dietary conditions, 3g.kg and 6g.kg of body-weight carbohydrate diets 32 hours before kickoff, to provide evidence based recommendations regarding nutritional intake and nutrient composition.
The data from this particular study are in review to be published but initial numbers show that all players arrived at the start of the game with similar amounts of muscle glycogen. This potentially may be due to the fact that in the days leading up to a game players will tend to taper training off, seeing a reduction in physical activity for example less time on feet, to allow players to be rested for the game. Importantly however, although both groups of players lost similar amounts of muscle glycogen in the game the 3g.kg players were nearing fatigue before full time and values show glycogen levels close to depletion.
Evidence based advice…
To minimise the above risk, I believe that if players are consuming a normal mixed diet consisting of high and low GI carbohydrates, good quality sources of protein, varied fruit and vegetable intakes and maintaining good hydration levels leading into a game, then arriving at game day fuelled adequately should be easily achieved. Additionally, consuming enough carbohydrates on the day of a game is easily achievable if consuming the right foods and fluids, for example carbohydrate based gels and drinks. As highlighted at the start, this will not be the perfect meal plan for every player, and depending on individual preferences fluids and/or other food sources may want to be substituted in to accommodate preferences.
Taken together, with recent novel evidence showing that a greater risk of premature fatigue occurs following a lower carbohydrate diet in the days leading into a game, we would highly recommend players to follow a carbohydrate diet closer to 6g.kg through a normal mixed diet.
James Morehen @1More_Nutrition
Balsom, P. D., Gaitanos, G. C., Soderlund, K., & Ekblom, K. (1999). High-intensity exercise and muscle glycogen availability in humans. Acta Physiologica Scandinavica, 165, 337 – 345.
Bangsbo, J. (1994). The physiology of soccer –with special reference to intense intermittent exercise. Acta Physiologica Scandinavica, 151 (suppl. 619), 1 – 155.
Iga, J., Scott, M., George, K., & Drust, B. (2014). Seasonal changes in multiple indices of body compositions in professional football players. International Journal of Sports Medicine, 35, 994–998.
Twist, C., Highton, J., Waldron, M., Edwards, E., Austin, D., & Gabbett. (2014). Movement demands of elite rugby league players during Australian National Rugby League and European Super League matches. International Journal of Sports Physiology and Performance, 9, 925–930.
Saltin, B. (1973). Metabolic fundamentals in exercise. Medicine and Science in Sports and Exercise, 5, 137 – 146.
James Morehen is the Sports Scientist at Nutrition X, Sports Performance Nutritionist at Widnes Vikings Rugby League team and lead strength and conditioning intern coach at Liverpool John Moores University.
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