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Author: Dr Matthew Campbell | PhD ACSM-CEP MIFST RNutr FHEA BSc hons.
Read time: 10 minutes
Food is made up from a combination of macronutrients and micronutrients. Macronutrients are nutrients that the body needs in large amounts and include carbohydrates, fats, proteins, and fibre, whereas micronutrients include vitamins and minerals. Achieving the right balance of macronutrients and ensuring adequate intake of micronutrients is important for maintaining energy balance – i.e., meeting, but not exceeding the body’s energy demands – as well as maintaining normal physiological processes that are important for day-to-day and long-term health.
What fuels are important for football?
Our bodies preferentially and predominantly use carbohydrate and fat as fuel sources. The amount of energy used, as well as the proportion of energy derived from carbohydrate and fat is influenced by several factors including genetics, training status, as well as what fuels are available – all of these factors differ between individuals meaning that generic, one-size-fits-all recommendations are usually inappropriate1. One constant however is exercise intensity and duration2. At lower exercise intensities (about 60%-70% of maximum heart rate – calculate your maximum heart rate by subtracting your age in years from 220), the body predominantly uses fat. With increasing exercise intensity and duration however, your body will turn to carbohydrate, such that at very high intensities (90%-100% of maximum heart rate) your body will be utilising carbohydrate almost exclusively2.
Why is having enough carbohydrate on-board important?
Having enough carbohydrate available to the body is important during football because low levels of carbohydrate availability is a major cause of early fatigue, decreased performance, reduced concentrations, and hypoglycaemia, especially towards the later stages of a match, extra-time, or long or intense training sessions3. Because the body has only a limited capacity for carbohydrate storage4, it is important to eat enough carbohydrate in the time leading up to a match. Data from a number of research studies show that carbohydrate intake before (and during) a match can delay fatigue5, enhance the capacity for intermittent high-intensity activities6,7 (such as sprint speed and recovery), and prevent hypoglycaemia when insulin doses are adjusted too8. It’s not known how much of the body’s carbohydrate stores are depleted during football, although previous research has suggested that about 50% of muscle fibres are empty or partially empty after a game9. Players who begin a game with lower muscle carbohydrate stores are known to cover less distance and much less at speed, especially in the second half and during extra-time periods, than those who have ensured adequate carbohydrate stores10.
How much carbohydrate should I eat?
On the days leading up to a match, training is usually light or avoided completely. During this time and on match day itself, carbohydrate intake can be increased to about 6-8 grams per kilogram of body weight per day11 (for a 70 kilogram person this equates to approximately 490 grams of carbohydrate across the whole day). This sounds a lot, but it can be easily achieved by incorporating carbohydrate-based foods (bread, pasta, and potatoes) into each meal. If you are playing in a tournament with congested match fixtures then carbohydrate intake should be maintained at about 6-8 grams per kilogram of body weight per day11 whilst you’re between games in order to replenish carbohydrate stores that may have been (partially) depleted. Although carbohydrate intake in the hours before a game is important, try and avoid eating immediately before (within an hour) and chose easily digestible foods (low in fibre) to avoid exercise-induced stomach upset12.
Is there a way to increase the amount of carbohydrate stored?
Interestingly, although there is an upper limit to the amount of carbohydrate that the body can store, this varies from person to person and can be improved using the right training and feeding strategies. For example, research has shown that training with low muscle glycogen levels can lead to ‘supercompensation’ – i.e., an increase in the amount of carbohydrate stored above and beyond an individual’s normal baseline level13. The challenge for people with type 1 diabetes adopting this strategy, however, is managing glucose levels during exercise to avoid hypoglycaemia. You can also try manipulating the type of carbohydrate consumed which has been shown to increased carbohydrate stores in some tissues14
Does it matter what time I eat carbohydrates?
The timing of carbohydrate consumption is important and can be manipulated to optimise carbohydrate storage. Carbohydrate-rich meals can be consumed on heavy training days, or specific times in the day when stored carbohydrate levels are low. For example, at breakfast the liver has partially depleted its carbohydrate stores because it has been releasing glucose during the night to maintain blood glucose levels15. When carbohydrate stores are low, the body is metabolically primed to preferentially restore these supplies, meaning that less of what you eat will be stored as fat, or ‘burnt-off’ as extra energy. Conversely, when carbohydrate stores are full, the body will is unable to store excess carbohydrate and so some of this will be stored as fat and some will be ‘burnt-off’ as extra energy.
Aside from carbohydrates, what else should I focus on?
Hydration is also key. Players should aim to start the match fully hydrated – you can tell if you are fully hydrated by the colour of your urine; anything darker than a pale-yellow colour and you need to drink more fluids. General recommendations are to drink 5-7 millilitres per kilogram of body weight in the 2 to 4 hours before kick-off (for a 70 kilogram person this equates to about half a litre. This allows sufficient time for excess fluid to pass through the system and achieve urine that is pale yellow in colour16. Make sure that your drinks are largely sugar-free (to avoid big glucose spikes) and try adding a pinch of salt (1 gram of table salt for every litre of water) as this helps increases hydration rates17.
If you are interested in learning how to improve managing your type 1 diabetes around exercise book a consultation with the author, Dr Matthew Campbell: firstname.lastname@example.org
Matthew is an internationally recognised research scientist specialising in exercise, diet, and type 1 diabetes. He also provides consultancy and diabetes coaching to people living with type 1 diabetes and those that support them.
Matthew has a PhD in nutrition and exercise metabolism, is author to over 150 research publications, and holds honorary titles with the University of Cambridge and University of Leeds. He is a certified clinical exercise physiologist accredited by the American College of Sports Medicine, a registered nutritionist, and a member of the Institute of Food Science and Technology. He also provides consultancy to professional bodies and professional athletes including NHS England, the World Health Organisation, and TeamGB.
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