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Transcript
Nutrition for Performance Objectives • Identify the components of a healthy, balanced diet • Recognise the key macronutrients required to lead a healthy lifestyle, and their important role/s in the body • Understand the difference between eating for health and performance • Describe the Glycaemic Index and it’s importance • Identify the importance of hydration for performance and the implications for a rider • Consider the use supplementation and identify possible issues for athletes Nutrition • Why do we need food? – Provide energy for the body to function – Provide energy for training • Fat: 9 cal/gram or 37 Kilojoules/gram • CHO: 4 cal/gram or 16 Kilojoules/gram • Protein: 4 cal/gram or 16 Kilojoules/gram – Help the growth and repair of muscle and body tissue – Help avoid and fight infection • Nutrition is recognised as a potential performance factor, together with speed, power etc. Dietary Nutrients Carbohydrate • Sugar – Pass into blood stream very quickly – Food/drink sources include soft drinks, sweets, honey, fruit juice dairy (i.e. yoghurt/milk) and fruit • Starch – Food sources Include pasta, cereals, breads, rice and potato • Starchy carbohydrates are broken down into sugar in the body, and are either stored in the liver or muscle as glycogen. • The liver can hold much more glycogen than skeletal muscle • Glycogen is broken down into glucose to be used for energy • After glycogen stores are full, excess dietary carbohydrate is converted to fat in the body • The amount of glycogen that can be stored is limited (approximately enough for a 1.5-2 hours, zone 3 ride) Dietary Nutrients Protein – Essential for the growth & repair of the bodies tissues – Proteins are made up of amino acids (20) • 12 – Non essential (synthesised by the body) • 8 – Essential (not synthesised by the body) – Essential Amino Acids must be supplied through diet – Animal food sources are considered to be of high biological value as they contain all the essential amino acids to build muscle tissue Dietary Nutrients Fat – Provides the most concentrated source of energy – Saturated – raises LDL i.e. Bad cholesterol – food sources include: – – – – – – Butter Cheese Chocolate Cream Full fat dairy Cakes – Monounsaturated - food sources include: – Olive oil, avocado, cashew nuts, almonds – Polyunsaturated - food sources include: – Oily fish e.g. salmon, fresh tuna (not canned) - important source of omega 3 which is good for concentration/heart health/inflammatory processes Dietary Nutrients Fat – Fat is used primarily for low intensity endurance exercise – Fat fuels are not as efficient as carbohydrates as more O2 is required – However there are greater fat stores in the body than CHO Dietary Nutrients Water – Key role in sustaining life – 55-65% adult body is water – Adequate levels of fluid are essential for; – Optimum storage of glycogen – Maintenance of the body’s core temperature Vitamins and Minerals – Vitamins assist with growth and maintenance of body functions – Minerals regulate the body's functions Dietary Nutrients Dietary Fibre – Roughage that is not digested by the body – 2 types: insoluble and soluble – Soluble: Helps to keep bowels healthy and prevents constipation. Found in fruit and vegetables. – Insoluble: decreases blood cholesterol. Found in oats, pulses and legumes. Eating for Health • • • Riders of all levels should initially focus on a healthy, balanced diet Avoid short cuts (i.e. supplementation) Variety Breakdown of Total Energy for Health Carbohydrate 55-60% Fat 20-35% Protein 15-20% Eating for Performance Dietary recommendations for performance similar to health Higher % CHO, lower Fat and Protein Increased volume of food Breakdown of Total Energy for Performance Carbohydrate 60-70% Fat 20-25% Protein 10-15% Eating for Performance Standard training loads – 7g of CHO per kilogram of body weight – 1.2g of protein per kilogram of body weight High training loads – 10g of CHO per kilogram of body weight – Up to 2.0g of protein per kilogram of body weight Example: 75kg rider completing standard training load – 525g of CHO per day – 90g of protein per day Eating for Performance: CHO & Protein Time Breakfast During ride Post ride Lunch Amount of food 4 x wheetabix 300ml skimmed milk Sprinkled with raisins (1 tbs) 250ml fruit juice 800-1000 mls sports drink Fruit smoothie (300ml milk, 1 x banana, 2 tbs honey) 4 slices granary bread 100 grams canned tuna + salad 1 x apple Amount of CHO (g) Amount of Protein (g) 51.4 15 17.3 25 9 10.2 0.5 Trace 50 70 Trace 10.2 57.6 Nil 22 25 10 Trace During ride Post ride 2 x CHO gels Fruit smoothie (milk, banana/s, natural yoghurt, honey) 50 70 Trace 10.2 Dinner 200grams cooked pasta (100g uncooked) 100g of grilled fish + salad/veg 50g of cheese 73 12 Nil Nil 20.2 12 37.1 5.5 526 g 7g/kg BW 136g 1.8g/kg BW Snack 1 carton of yoghurt + ½ can stewed fruit (natural juice) TOTAL Glycaemic Index • The glycaemix Index is a ranking of CHO foods on a scale from 0100 according to how they affect blood glucose levels. • 3 categories: • LOW (<55) – e.g. Oats/lentils/fresh fruit/yoghurt/sweet potato. • MODERATE: (55-69) – wheetabix, wholemeal bread, dried fruit, new potato. • HIGH: (>69) – Jasmine rice, sweets, white bread etc. • One of the critical factors for performance is how readily available glucose is to a rider • Glycaemic Index (Gi) provides a measure of how fast and how much a particular food raises blood glucose levels • The GI can therefore be used to assist the selection of appropriate foods at the appropriate times Glycaemic Index • Before exercise: – Low to Moderate GI – 2-3hrs prior to exercise – Long and sustained release of glucose into the blood • During exercise – High GI – Provides a rapid release of glucose into the blood • Post exercise – When? • Immediate – High GI (e.g. sports drink) • Extended – Medium GI (e.g. yoghurt and fruit) Glycaemic Index Time Glycaemic Index Examples Before exercise Low/moderate Porridge Fruit (eg pear, apple, orange, plum, peach) Dried fruit (eg prunes, apricots) Breakfast cereal (eg All-Bran, muesli) Skimmed or low-fat milk During exercise High Energy gels (exercise lasting longer than 60 minutes) Sports drinks (exercise lasting longer than 60 minutes) After exercise High (immediately after exercise) Sports drinks Cornflakes Rice cakes Bagels Bananas Low/moderate (1-2 hours after exercise) Wholemeal bread Potatoes Rice Couscous Instant oats Breakfast cereals (eg Special K, Weetabix) Pasta Race Feeding Strategy Road Race What ? How much ? CMC TRAINING SESSION 18 Race Feeding Strategy • Endurance disciplines (>2hrs) requires careful consideration for feeding during the race Why does it help? • Maintains concentration of blood glucose – provides a constant supply of glucose • Helps maintain high rates of carbohydrate oxidation • A regular intake of CHO ‘saves’ glycogen breakdown in liver and to a small effect muscles (protects stores) • Improves performance and delays the onset of fatigue CMC TRAINING SESSION 19 Race Feeding Strategy • Different types of CHO – Separated by ‘rate’ of oxidation – Slow oxidation – up to 30g / hour – Fast oxidation – up to 60g / hour Slow Fast Fructose (fruits) Glucose (breakdown of starch) Galactose (sugar beets) Sucrose (table sugar) Isomaltulose (honey) Maltose (two glucose molecules) Amylose (starch breakdown) Maltodextrins & Amylopectin (starch breakdown) CMC TRAINING SESSION 20 Race Feeding Strategy How much carbohydrate and which type? • ‘Optimal’ intake is the maximum amount of CHO that results in highest CHO oxidation • Is more better? – ‘The pack says one scoop, so I’ll give myself two. It must be better!’ – Do you include as much CHO into a drink as possible? • Limits of uptake – Human intestines use specific ‘transporters’ to move CHO from the intestinal space, through the intestinal wall and into the blood. – Limited availability of ‘transport’ across the intestinal wall – At full capacity, glucose has a transport limit of 60g / hour CMC TRAINING SESSION 21 Race Feeding Strategy How much carbohydrate and which type? • Are there other transporters available? – Fructose uses a different transporter – Therefore could a combination of Glucose and Fructose increase the CHO update? • Glucose and Fructose mixes shown to increase CHO oxidation with a 2:1 ratio – Glucose: 60g / hr – Fructose: 30g / hr – Interestingly, if glucose is not at it’s ‘maximum’ (ie. 60g/hr) the increase oxidation is not seen CMC TRAINING SESSION 22 Race Feeding Strategy Race Feeding Strategy • Many different combinations of CHO have been research – Currently the following combinations have been identified as the most beneficial CHO Type Amount Glucose + fructose 60g / hr + 30g / hr Maltodextrin + fructose 60g / hr + 30g / hr Glucose + sucrose + fructose 60g / hr + 15g / hr + 15g/ hr – Maltodextrin is less sweet than both glucose and fructose, therefore it may be easier to consume • Are the above rates affected by body mass? – No changes seen by variation in athletes mass CMC TRAINING SESSION 24 Race Feeding Strategy Solid CHO v Liquid CHO? • Energy bars and Gels V drinks? – Equally as effective at increasing CHO oxidation rates as ingesting a CHO drink – Therefore providing greater range and ‘comfort’ for athletes to choose a multiple range of CHO sources • Types of solid race food? – Pastries / cakes are the ‘traditional’ food choice that typically are high in fat – Look at alternatives – rice cakes, small sandwiches etc, with lower fat CMC TRAINING SESSION 25 Race Feeding Strategy Carbohydrate intake during exercise Event < 30min Suggested intake CHO No CHO needed CHO Type Glu Glu + Fru - - - - 30 – 75min V small amounts Small sips / mouth wash Most forms of CHO Yes Yes 1hr – 2hr Small amounts Up to 30g/hr Most forms of CHO Yes Yes 2hr – 3hr Moderate amounts Up to 60g/hr Rapidly oxidised CHO Ok Yes - Yes (glucose, Multodextrins) 2.5hrs + Large amounts Adapted from A. Jeukendrup, INSEP Eat to Win conference Up to 90g/hr Multi-transport CHO CMC TRAINING SESSION 26 Hydration • • Crucial for health and performance For optimum performance water and electrolyte balance must remain constant • • • • Dehydration by as little as 2% loss of body weight starts to impair performance Dehydration in excess of 5% loss of body weight can decrease work capacity by 30% Heat illness can occur when 5-6% body weight is lost MYTH – dehydration cannot be tolerated or trained – any dehydration will reduce performance Hydration How to combine CHO intake whilst maintaining hydration in different environments? Hydration What to Drink, When to Drink • Isotonic drinks – CHO of 5-8% – Provides source of energy, without impairing fluid absorption – Use pre, during and post training / competition • Hypotonic drinks – Contains CHO and salt – Limited CHO, therefore limited contribution to performance – Useful in hot conditions • Hypertonic drinks – CHO of 10% + – Could limit hydration purposes – During and post training competition • Some evidence suggests that glucose + fructose combinations aids delivery of water compared to just glucose. Hydration Recommended drinks for varying intensities and durations Exercise Intensity and Duration Type of Drink • Low/moderate/high – less than 30 minutes • Water/diluted squash • Low/moderate – less than 60 minutes • Water/diluted squash • High – less than 60 minutes • Isotonic sports drink • High - longer than 60 minutes • Isotonic sports drink Hydration Approximate fluid intake requirements per hour Temperature Body Weight (up to 14ºC) Kg (15-24ºC) (over 25ºC) Fluid Requirements in ml 40-50 200-300 300-450 450-550 50-60 250-400 400-500 500-600 60-70 300-450 450-500 550-650 70-80 350-500 500-650 650-750 80-90 400-550 550-700 700-850 Pre-Race Meal • Pre-Race meal tops up stores and keeps the stomach comfortable during races • Keep meals familiar and individual • Track: – Multiple competitions – No feeding during races – Easy access to regular feeding (track centre) • Road: – Normal sized meal 4hrs before race (high CHO, low fat) – Include a small snack 2hrs before – If a rider suffers from pre-race nerves, try a liquid meal supplement or a fruit smoothie as a pre-race meal. – Include fluid throughout Carbohydrate Loading • Strategy involving altering training and diet, to maximise stores of glycogen (carbohydrate) prior to competition • Original design required 3-8 days – 3-4 day Depletion Phase (high training load & low CHO) – 3-4 day Loading Phase (low training load & high CHO) – Negative effects of strategy included impact on training, reduced mental capacity and changes in mood state. • Amended design requires 3-4 days – 3-4 day Loading Phase (tapering training load & high CHO) – Limited effects of strategy on training, mental capacity or mood state. • Both designs shown increases in muscle glycogen stores: – 100-120 mmol/kg ww – normal glycogen levels – 150-200 mmol/kg ww – post loading Carbohydrate Loading • Some research indicates that female riders may be less responsive to CHO loading than males • More research is needed • Common mistakes – Not combining appropriate dietary intake with training load taper – Athletes gorging on food to increase their CHO intake – Fear of weight gain preventing athletes from loading properly • Body mass can increase by 2kg – Not reducing intake of dietary fibre, leading to discomfort because of volume of food required – Not maintaining appropriate hydration Carbohydrate Loading: Example daily diet Time Breakfast Food 3 cups of low fibre cereal & 1.5 cups of low fat milk 1 medium, ripe banana 250ml apple juice Snack 500ml sports drink Toasted white bread with jam Lunch 2 sandwiches (4 slices of bread) with salad and tuna filling 2 x 125g low fat yoghurt 375ml can of soft drink Snack Dinner Snack Fruit smoothie (low fat milk, 1 banana, 1 tablespoon of honey Cereal bar 2 cups of pasta 1 cup of tomato sauce 3 slices of bread 2 glasses of squash Toasted muffin and honey 500ml sports drink Sample Plan contains approximately: 650g Carbohydrates, 125g Protein, 60g Fat Post-Race / Training Meal • Focuses on the replenishment of energy and rehydration • Immediately: – Within first hour – CHO & Protein has been shown to aid replenishment of glycogen stores – For every 4g of CHO, 1g of Protein • E.g. Rice & tuna (CHO, Protein) • Rice also helps to ‘rehydrate’ given it’s high water content • Delayed: – Within 2hrs – A CHO rich meal with protein included – Don’t forget micro-nutrients! • Consider post race ‘availability’ of food – Media, anti-doping, massage etc. Supplements • What are supplements? – Additional sources of either macro or micro nutrients taken in addition to standard meals • Endurance cycling is one of the most demanding of disciplines: Can a rider get all nutrients they need from food alone? – Yes, but it is not always practical • What role do supplements play? – Convenient, support performance • Are there any potential issues of taking supplements? – Possible contamination, dependency, incomplete nutrition Supplements • • Should be viewed as ‘supplements’ to diet, not replacements Check evidence claims – Endorsements by athletes / coaches • • • • • No guarantee Use based on dietary requirements Supplements are unregulated and may contain prohibited substances that are not listed on the label Claim to be ‘IOC’ or ‘WADA’ approved but the IOC or WADA do not endorse supplement products No guarantee can be given about the safety or legality of supplements Fact or fiction Skipping breakfast help athletes loose weight • Fiction – blood glucose levels will already be low as athletes may not have eaten for 8-12 hours. Skipping breakfast decreases the metabolic rate which makes it harder to burn calories. It is important to eat a CHO snack before an event • Fact – fuelling the body with carbohydrate before training or an event is beneficial to provide fuel so that muscle glycogen stores last longer You don’t need to eat after exercising • Fiction – it is important to fuel the body firstly with a high GI CHO food source to start replenishing glycogen stores. Ths is especially important if the next major meal is delayed. Fact or fiction You can get all the nutrition you need from energy bars • Fiction – Energy bars can contain the same amount of calories as a small meal (e.g. sandwich & fruit). Therefore, they are unsuitable for athletes performing very light training schedules. They should only be used if athletes require more CHO/energy which cannot be met through eating increased volumes of food. In this situation, energy bars should compliment not supplement their meals You need to loads of protein to enhance performance • Fiction – CHO is the nutrient that will enhance performance. It is the body’s preferred fuel. It is still important to follow the recommended guidance for protein intake, but it is not an effective energy source. Fact or fiction It is better to drink sports drinks containing sodium rather than water when competing in hot climates • Fact – in hot, humid environments dehydration is a particular concern for those athletes who sweat heavily, those who perform for long periods or athletes who are acclimatising to a hotter climate or going to altitude. Sports drinks containing sodium in these situations are more suitable than water to replace the electrolytes lost with sweat You can eat whatever when you want when you train • Fiction – Athletes can generally consume more total energy. However, increased energy requirements should come from CHO not fat. Athletes should not eat too many high fat or treat foods as this could compromise training and recovery.