2.1 Diet and Nutrition

2.1 Diet and Nutrition

Specification

2.1.1 Dietary Manipulation for Performance

2.1.2 Optimal Weight and Energy Balance Energy Balance Energy Input = Energy Output Positive Energy Balance Energy Intake > Energy Output Negative Energy Balance Energy Intake < Energy Output

2.1.2 Optimal Weight and Energy Balance It is crucial that performers meet their energy needs during periods of training If not, this can result in: • Muscle loss (atrophy) • Decreased intensity and duration of performance • Slow recovery rates • Increased risk of injury, fatigue and illness Therefore any weight loss strategies should bescheduled into a training plan AWAY from heavy training/competition e.g., Base phase

2.1.2 Optimal Weight and Energy Balance • Different sports require different optimal weights and manipulation of diet can be used to achieve this. • For example boxers trying to make a weight category (up or down in weight), a Sumo wrestler trying to be as heavy as possible, or a cyclist being light to find an optimal Power to Weight ratio.

2.1.2 Optimal Weight and Energy Balance Energy is the ability to perform work (measured in joules) 4.18 joules = 1 calorie But what does caloric requirement depend upon?

2.1.2 Optimal Weight and Energy Balance Basal Metabolic Rate = The minimum amount of energy needed to sustain the body’s essential physiological functions whilst at rest. (accounts for around 75% of total energy expenditure)

2.1.2 Optimal Weight and Energy Balance Metabolic Equivalent Tasks (METs) calculate the energy expenditure of physical activity. The ratio of a performer’s working metabolic rate relative to their resting metabolic rate Uses oxygen consumption per unit of body weight per minute to estimate exercise intensity (ml O2/kg/min)

2.1.2 Optimal Weight and Energy Balance 1 MET = 3.5 ml/kg/min or 0.0175 kcal/kg/min This is your resting VO2 (volume of oxygen consumed). This is roughly 1 kcal (calorie) per hour. 2 METS indicates the energy expended is twice that of when resting.

2.1.2 Optimal Weight and Energy Balance Calculate the daily energy expenditure for the following person; Age: 17Gender: Male Height: 1.75 Weight: 75kg Daily Activity 10hrs sleeping 3.5hrs walking (4.8km/h) 4hrs watching television 6.5hrs studying

2.1.2 Optimal Weight and Energy Balance General recommendations suggest that a person’s calorie intake should consist of roughly 45-65% Carbohydrate 20-35% Fat 10-35% Protein The relative contribution depends on the needs of the individual eg., a power athlete may take in more protein and an endurance athlete more carbohydrate.

2.1.3 Hydration

2.1.3 Hydration and fluid • Fluid loss can have a big impact on performance in Sport. Loss of sweat equal to 2% of body weight causes a noticeable decrease of physical and mental performance. Losses of 5% or more of body weight during physical activities may decrease the capacity for work by roughly 30% • Dehydration may cause a reduction in blood volume, decreased skin blood flow, decreased sweat rate, decreased heat dissipation, increased core temperature and an increased rate of glycogen use. • The intensity, duration, heat, humidity and size of an individual all affect hydration status.

Hydration and Fluid Intake • Dehydration reduces plasma volume and therefore increases blood viscosity, central venous pressure decreases and reduces the amount of blood returning to the heart. During peak athletic intensity, these changes can decrease the amount of blood entering the heart during diastole. • Less blood entering the heart during diastole decreases the amount of blood that may possibly leave the heart during systole, the phase where the heart contracts, consequently decreasing cardiac output and performance. • Cardiac Drift can occur in prolonged activities as the body tries to maintain cardiac output.

2.1.3 Hydration • An increased core temperature during a dehydrated state is accompanied by a larger aromatic amine response, possibly leading to an increased rate of glycogen breakdown in muscles. • An increased rate of glycogen breakdown may contribute to an increased level of fatigue in the muscles used during the athletic activity. • The breakdown of glycogen during exercise leads to an intracellular increase of lactate. As lactate is produced by the breakdown of glycogen, pH decreases causing skeletal muscle fatigue.

2.1.3 Hydration

2.1.3 Hydration All sports drinks are not the same. They fall under three categories Isotonic, Hypotonic and Hypertonic. Isotonic = similar concentration to blood Most traditional sports drinks (like Gatorade, Powerade, Aquarius) technically fall into the ‘isotonic’ category. Similar in osmolality to human blood. Theoretically they deliver a reasonable amount of energy and clear the gut promptly too, if not quite as fast a hypotonic solutions. They're usually around 6-8% carbohydrate.

2.1.3 Hydration This can be useful for shorter duration, high intensity exercise where getting carbohydrate in quickly can be more important than warding off dehydration. Whilst isotonic drinks tend to sound great on paper, something of a ‘jack of all trades’, in the real world they can cause quite gastrointestinal upset - i.e. a sickly, bloated stomach - when consumed in large quantities. Often the case in long endurance events, especially the case in hotter conditions, where high sweat rates drive a faster rate of drinking, or when combined with carb snacks like gels and energy bars.

2.1.3 Hydration Hypertonic = higher concentration than blood Hypertonic drinks are more concentrated than your blood. That's usually because they're formulated with lots of carbohydrates in order to maximise energy delivery as a way to fuel high intensity activities. Most recovery drinks also fall into this category, often including added protein. Deliver large amounts of calories or certain macronutrients quickly and efficiently into the bloodstream. Liquid calories tend to be more readily absorbed than solids, which need more work from the body to break them down first.

2.1.3 Hydration Where they can cause issues though is if you’re trying to use a hypertonic drink at times when fluid intake is the priority and dehydration is a concern; such as during long duration activities where you’re sweating a lot. Hypertonic drinks cause the concentration of fluid in your intestine to becomes hypertonic. Your body then has to first move water out of the bloodstream back into the intestine to dilute the solutes to a level that allows absorption of nutrients and fluids into your body. This net movement of water from the blood into the intestine is therefore technically dehydrating you. It's moving water out of the blood into the gut when what you actually want to do is increase your blood fluid levels.

2.1.3 Hydration Hypotonic = lower concentration than blood Lowest carbohydrate concentration but fastest absorption. Hypotonic drinks should thereforebe your preferred option if the primary goal of your drink is hydration rather than delivery of large amounts of energy. Electrolytes and a small amount of glucose in sports drinks can actively cause faster absorption of fluids rather than relying solely on osmosis. These electrolytes also replaces those that are lost through sweating.

2.1.4 Supplementation https://jissn.biomedcentral.com/track/pdf/10.1186/s12970-018-0242-y The supplements industry is becoming bigger and bigger each year and expected to reach a global value of around 250 billion Euros by 2024.

2.1.4 Supplementation An ergogenic aid is any training technique, mechanical device, nutritional ingredient or practice, pharmacological method, or psychological technique that can improve exercise performance capacity or enhance training adaptations

2.1.4 Supplements - Creatine Monohydrate One of the most popular, effective supplements. It is naturally found in muscle cells and chemically quitesimilar to Amino Acids. The amount of meat you eat, exercise you do, testosteronelevels can all affect your natural Creatine stores. Supplementations increase your bodies Phosphocreatinestores which allows more ATP production, increasing workload. Potentially also increases some anabolic hormones and recent research suggests it helps with some brain health markers too.

2.1.4 Supplements - Creatine Dosage; To load with creatine, take 20 grams per day for 5–7 days. This should be split into four 5-gram servings throughout the day. Maintenance phase of 3-5g per day after that. Taken in the form of powder dissolved in liquid or tablet form.

2.1.4 Supplements - Creatine Increases high intensity exercise capacity and muscle mass. Studies show 1-2kg increase in muscle mass vs controls. Improvements come from an ability to perform more highintensity work and therefore promote greater adaptations Impaired kidney function* Weight gain from water retention also dehydration* Gastric distress* * Anecdotal evidence - studies suggests to be safe

2.1.4 Supplements - Creatine 1) What is creatine? 2) What type of athlete would benefit from taking a creatine monohydrate supplement? 3) Identify the advantages and disadvantages of using a creatine monohydrate supplementation?.

2.1.4 Supplements - Creatine 1) What is creatine? • Creatine is a natural substance found in skeletal muscle. • Stored as phosphocreatine (PC). 2) What type of athlete would benefit from taking a creatine monohydrate supplement?• Since energy derived PC is anaerobic and explosive, power athletes such as weight lifters, sprinters, gymnasts and throwers would benefit from taking creatine monohydrate supplement. 3) Identify the advantages and disadvantages of using a creatine monohydrate supplementation?Advantages: • Increase in PC stores, thereby delaying alactic/lactic threshold. • Which means that athlete can apply maximum power for longer.Disadvantages:• Associated muscle cramps. • Weight gain. • Heat-related symptoms such as dehydration. • Renal stress.

2.1.4 Supplements - Protein Recommendation 1.2 to 2.0 grams of protein per kilogram of body weight per day for athletes. This is depending on training load at the time. Protein intake should be spaced throughout the day and after workouts. Most official nutrition organizations recommend a fairly modest protein intake. The DRI (Dietary Reference Intake) is 0.8 grams of protein per kilogram of body weight.

2.1.4 Supplements - Protein If an insufficient amount of protein is consumed, an athlete will develop and maintain a negative nitrogen balance, indicating protein catabolism and slow recovery. Over time, this may lead to muscle wasting, injuries, illness, and training intolerance.

1.2.4 Supplements - Protein It is not essential to supplement protein with the best dietary sources of low fat, high quality protein are light skinless chicken, fish, egg whites, very lean cuts of beef and skim milk (casein and whey). Athletes however often prefer the ease of Protein supplements which are often made from Whey, Casein and plant based proteins such as rice, soy and pea. Absolute doses of 20-40g are thought to maximally stimulate protein synthesis.

2.1.4 Supplements Supplements are a convenient way of meeting protein intake recommendations. Promotes lean tissue growth and recovery. Some gastric distress, especially for those intolerant to lactose (apart from plant protein sources). Possible link to kidney and liver disorders if taken in excess. Debate whether necessary when diet can provide all required protein.

2.1.4 Supplements - Caffeine Caffeine is a naturally derived stimulant found in many nutritional supplements typically as guarana, coffee, tea, soft drinks, energy drinks, and chocolate. Caffeine has also been shown to be an effective ergogenic aid for aerobic and anaerobic exercise with a documented ability to increase energy expenditure and promote weight loss. Studies indicate that ingestion of caffeine (e.g., 3–9 mg/kg taken 30–90 min before exercise) can spare carbohydrate use during exercise and thereby improve endurance exercise capacity.

2.1.4 Supplements - Caffeine Caffeine has been shown to improve repeated sprint performance as well as some/limited evidence that maximal strength is improved. Caffeine is on the WADA “monitoring list” which means they are checking to see patterns of misuse and if it should be banned or not.

1.2.4 Supplements - Caffeine Stimulates CNS therefore can increase reaction time. Diuretic properties leading to water loss. Can promote fat metabolism causing weight loss and increased endurance (glycogen sparing effect). Diuretic properties causing dehydration and exacerbating heat exhaustion. Can cause nervousness and jitters (shaking). Disrupted sleep patterns Caffeine addiction and subsequent withdrawal symptoms .

2.1.4 Supplements - Bicarbonate Loading During high intensity exercise, acid (H+) and carbon dioxide (CO2) accumulate in the muscle and blood. The bicarbonate system is the primary means the body rids itself of the acidity and CO2 via their conversion to bicarbonate prior to subsequent removal in the lungs. Bicarbonate loading (e.g., 0.3 g per kg taken 60–90 min prior to exercise or 5 g taken two times per day for 5 days) as sodium bicarbonate has been shown to be an effective way to buffer acidity during high intensity exercise lasting one to 3 min in duration.

2.1.4 Supplements - Bicarbonate Loading Increased performance in prolonged, high intensity activities lasting 1-3 minutes. Cramping, bloating, diarrhoea.

2.1.4 Supplements - Contemporary Supplements Ginseng - Popular from Chinese medicine suggested to increase mental alertness, boost energy levels and the immune system. Glucosamine - Reported to reduce joint inflammation and stiffness. Arnica - Used to reduce inflammation, bruising and pain. Camomile - Reduce stress, support immune system and promote tissue repair. The world of supplements is continually evolving... https://www.deliciousliving.com/supplements/game-5-new-performance-boosting-supplements/

2.1.5 Optimising Nutrition for Performance Nutrition is an area that athletes will attempt to optimise in order to improve their performance. This may be through the way they eat; -During day to day life. -Immediately before a competition. -During training sessions or competition.

2.1.5 Optimising Nutrition for Performance - Carbohydrate loading Carbohydrate loading, commonly referred to as carb-loading or carbo-loading, is a strategy used by endurance athletes (events over 120 mins), to maximise the storage of glycogen in the muscles and liver. The science and practice in this area has shifted a lot in recent years. Previously a 'classic' approach involved training hard to deplete the body's glycogen, followed by a seven-day, high carbohydrate diet to replenish stores.

2.1.5 Optimising Nutrition for Performance - Carbohydrate loading This protocol involved an extremely hard workout 7 days before the race, followed by carbohydrate restriction for 3 days. It may not be ideal to have such a hard workout 7 days before. Without carbohydrate recovery in the days after is likely to be very poor. Athletes were also recommended not to exercise the week before the race. The high fat, no carb diet in the 3 days after the glycogen depleting exercise also caused a lot of gastro-intestinal problems in many runners.

2.1 Diet and Nutrition