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Transcript of Sports Nutrition
1 Nutritional Requirements
2 The Strcture and Function of the Digestive System
3 Energy Intake and Expenditure in Sports Performance
4 Hydration and sports performance
5 Planning a Suitable Diet.
Unit 11: Sports Nutrition
All perform essential roles in the human body.
Macronutrients are the main components of our diet.
All three macronutrients are needed in the diet, as each perform vital functions in the body.
Vitamins and minerals are required in smaller amounts than fats, protein and carbohydrates. However, they play a critical role in regulating chemical reactions in the body.
Is a complex carbohydrate which is thought to help in the prevention of certain diseases such as cancer of the colon, diabetes, heart disease and irritable bowel syndrome.
A high fiber intake also keeps your bowel functioning efficiently.
The amount of nutritional requirement you need depends on age, sex, level of activity and state of health.
Some nutrients are more essential during different stages of life e.g. calcium in childhood and iron during pregnancy.
Recommended daily allowance (RDA)
Estimated average requirement
Function of the digestion system
The mechanical and chemical breaking down of food into smaller components, to a form that can be absorbed, for instance, into a blood stream. Digestion is a form of catabolism; a break-down of macro food molecules to smaller ones. It involves enzymes in the gut to help break down the food.
The movement of digested food from the stomach and small intestines into the body tissues and blood. Absorption happens in the villi that line the small intestine.
This is the removal of potentially poisonous end-products from metabolism, normally in your urine and faeces. Kidneys play a huge part in excretion of urine and large intestines eliminate solid or semi solid waste.
The kidneys are in charge of keeping the blood constant by filtering it to remove any excess water and waste products which are then secreted. Every 24hrs the kidneys filter around 150 litres of blood and produce around 1.5 litres of urine.
Energy intake and expenditure in sport performance
Energy is obtained from foods you eat and used to support your BASAL METABOLIC RATE;
The minimum amount of energy required to sustain the body's vital functions in a waking state, and all activity carried out at work and leisure.
Measured in calories and joules, which are units that are very small so they are multiplied by 1,000 and referred to as kilocalories (UK) or kilojoules (metric or international)
The most commonly used method of classification of body type is known as SOMATOTYPING.
This Recognises 3 basic body types:
Ectomorph Mesomorph Endomorph
Factors that effect basal metabolism
There is an energy balance if the food and drink you take in (energy input) equals the amount of energy you expend (energy output). This means you will not gain or lose any weight.
There are four major components to energy output:
Resting metabolic rate
The amount of energy required to maintain the body of an individual in a resting state.
Your basal metabolism represents the number of calories your body burns when at rest, but awake, over the course of one day.
This number is one of the factors that determines your total calorie needs for the day.
your BMR reduces with age. After 30, it will fall by 2% every 10 years.
Males generally have greater muscle mass than females so their BMR will be higher.
exposure to hot or cold climate causes an increase in basal metabolism to maintain the body's internal temperature.
to estimate your total energy requirements you need to consider your physical activity level (PAL). Simplest form is multiplying your BMR by your PAL.
Water is an important nutrient for life because it helps regulate our temperature, lubricate our joints and transport nutrients throughout the body. Around 60% of our body weight is made up of water and it is vital to maintain that balance so that your body and mind can function correctly.
Water is lost through a number of routes such as urine, faeces, evaporation from the skin and expired breath. If your losing more water than you take on your body becomes dehydrated.
Dehydration can cause reduce strength, power and aerobic capacity. Heatstroke is a serve and maybe fatal. What are the warning signs of dehydration?
Is a state of increased hydration, producing a greater than normal body water content. Starting exercise in this state can improve thermoregulation, improving heat dissipation and exercise performance.
Is a state of decreased hydration, producing a less than normal body water content. It increases core body temperature, impairs sweating response and causes skeletal muscle fatigue.
Is a state of hydration achieved by manipulation of the ergogenic aid glycerol. When ingested with large volumes of water (1-2litres), glycerol has been shown to increase water retention in the body. This reduces overall heat stress during exercise in hot conditions, lowering heart rate and body temperature. However, there can be some side effects such as headaches, dizziness, stomach aches and bloating.
A human is required to drink 2-2.5 litres of fluid per a day (6-8 cups). 10% of this comes from your metabolic processes that release water within your body and the other 90% is from your diet. (60% comes from fluid and the rest from food).
Sports performers should have a frequent fluid intake during pre-event, inter-event and post-event.
How can you check if your hydrated or not?
Water is the main fluid consumption however, some sports performance drinks may be useful for high intensity training.
Hypotonic- These drinks are absorbed rapidly from the intestine, and are good for rapid fluid replacement during and after exercise. These drinks are usually lower in calories than other types of sports drinks, and are therefore also suited for everyday consumption.
Hypertonic- drinks are best used after long endurance events to replenish glycogen stores, or for “carbohydrate loading” in the days prior to an endurance event. Hypertonic fluids are absorbed more slowly than isotonic or hypotonic drinks - water is drawn into the intestine to dilute hypertonic drinks prior absorption. Therefore, hypertonic drinks are not appropriate for use during exercise, only several hours before or after exercise.
Isotonic- allows for relatively rapid absorption of the ingested fluid from the stomach and small intestines. This allows for rehydration during exercise, and supplies fuel (simple carbohydrates) and electrolyes (critical for body function) to keep the athlete functioning at peak levels during endurance events.
Provides the correct amounts of ( ) without ( ) or ( ).
Food Deficiency Energy Nutrients Excess High Low
Why do you need a balanced diet?
What are the components and how do they contribute to a balanced diet?
How do activities determine the diet plan?
Why would timing of the season have an impact on a diet?
British Association of Sport and Exercise Sciences www.bases.org.uk
British Nutrition Foundation www.nutrition-org.uk
Food Standards Agency www.foodstandards.gov.uk
Institute of Food Research www.ifrn.bbsrc.ac.uk
Sports drinks for athletes
Eat well plate
How should your diet change?
is necessary for breaking down carbohydrates and starches.
is responsible for the digestion of proteins, which are very hard to assimilate
is needed for breaking down fats, triglycerides in particular. These are required for proper intestinal absorption of nutrients.
You need to know:
: measures (calories, joules, kilocalories, kilojoules);
, eg fats, carbohydrates, proteins;
, eg body composition, lean body mass, percentage body fat (skinfold analyses, bioelectrical impedance analysis, hydrodensitometry); body weight; calorimetry (direct, indirect)
: basal metabolism; age; gender; climate; physical activity
You need to include:
Hydration: signs and symptoms (dehydration, hyperhydration, hypohydration, superhydration); fluid intake
(pre-event, inter-event, post-event); sources, eg water, sports drinks (hypertonic, hypotonic, isotonic)
Effects on sports performance: eg frequency, intensity, duration, specificity, progression, recovery
Diet: balanced diet (carbohydrates, fats, proteins, water, fibre, vitamins, minerals)
Activities: eg aerobic, anaerobic, muscular strength and endurance, flexibility; timing, eg pre-season, midseason,
post-season, pre-event, inter-event, post-event
- The energy required to raise 1 gram of water by 1 degree C.
- 1 joule of energy moves a mass of 1 gram at a velocity of 1 meter per second.
Approx 4.2 joules = 1 calorie
- The energy required to raise the temperature of 1kg of water by 1 degree C. Equal to 1,000 calories and used to convey energy of food. Often simply referred to a scalories.
- A unit of measurement for energy but like the calorie, a joule is not a large unit of energy; therefore kilojoules are more often used.
1 gram fat = 9.0 kcal = 38KJ
1 gram carbs = 4.0 kcal = 17KJ
1 gram protein = 4.0 kcal = 17KJ
Fat and carbohydrate are the main sources of energy fuel for the body.
Glucose is the preferred fuel for exercising muscles particularly when the intensity increases.
Protein may be used during prolonged periods of exercise.
If the energy is not replaced as it is used, the muscles will tire and be unable to maintain high intensity.
Large bone structure
Delicate bone structure
Finds weight gain difficult
A heavy build
Tendency to gain weight
Generally finds weight loss difficult
Lean Body Mass
Body composition refers to the lean body mass and body fat that make up total body weight.
Lean body mass includes bone, muscle, water, connective and organ tissues.
Body fat includes both essential and non-essential fat stores.
Energy expenditure can be assessed by direct and indirect calorimetry, essentially through the measurement of heat production.
Direct calorimetry (DC) measures the actual amount of heat produced by the body. It uses an airtight chamber where heat produced by the subject warms water around them.
Indirect calorimetry (IC) estimates heat production by measuring respiratory gases. A mouthpiece and Douglas bag collection or mouthpiece and gas anaysis system, with energy consumption calculated from the amount of oxygen consumed.
Is also known as body mass and is measured in kilograms. Over eating can cause obesity and being over weight causes health issues. Some sports are categorised based on body weight such as boxing. However, If people do not follow the energy and nutrition guidelines they can also suffer form health problems.
What other sports can you think of?
Percentage of Body Fat
Unlike basic body type, it is possible to change body composition.
Exercise will generally have the effect of increasing lean body mass and decreasing body fat.
Methods of assessing % Body Fat
- Skinfold Analysis
- Bioelectrical Impedance Analysis
- Hydrodensitometry (underwater weighing)
When assessing % body fat over time, ensure that;
- You always use the same method
- The same person carries out the assessment each time
- Measurements are made at the same time of day
Bioelectrical Impedance Analysis
Energy expenditure that occurs as a result of environmental or physiological stresses placed on your body.
Things like a change in temperature that may require you to shiver or stress that may cause you to fidget.
Resting Metabolic Rate
Can account for 60-75% of total energy output
Largest component of total energy expenditure
Closely related to lean body mass and so is influenced by body composistion
Muscle tissue is more metabolically active than fat tissue.
Gains in muscle mass will result in increases in RMR.
Also influenced by age, sex, and genetic background
Refers to energy expended above that of RMR.
Processes of digestion, absorption, transport and storage of food.
Influenced by calorie content and composisiton of diet
Higher enrgy intakes and regular eating patterns are thought to help maintain higher rates of dietary thermogenesis
Skipping meals and restrictive diets reduce this component of energy expenditure
Most variable component of energy expenditure
Additional energy expended above RMR and DT.
Contribute more in active individuals
Exactly how much depends on how active your lifestyle is, how intense and how long you participate in exercise and the type of exercise.
Look at your energy requirements and those of others
How much can you consume?
Why might they be different?
Do you think you consume the correct amount, too little, or too much?
Think about the food that you eat, how many calories do you think you consume?
Do you know where to find information on energy content of food?
Your Energy Requirements
Total energy requirements = 3000
Find 1% - 3000 / 100 = 30
Carbs (50-60%) 50% = (30 x 50) 1,500
60% = (30 x 60) 1,800
Carbohydrate intake would be 1,500 – 1,800 kcal per day.
Do the same for your fat and protein intake.
Work it out!
You can now predict your carbohydrate, fat and protein requirements.
In general, athletes will require an energy distribution of;
50 – 60% of calories from carbohydrates
12 – 15% from protein
25 – 30% from fat
To work out your energy requirements for a typical day, you need to:
BMR x PAL = Your calorie requirements
What are your energy requirements?
Eg Calculation of PAL (Male):
Occupational PAL = Light
Non-occupational PAL = Very Active
Estimated PAL = 1.6
Physical Activity Level (PAL)
Using the following work out your own BMR
Eg Male, 16yrs, 60kg
(17.1 x 60kg) + 657 = 1683 calories per day = BMR
When energy intake exceeds expenditure, this is referred to as
positive energy balance
weight is gained.
If intake is less than requirements, the additional energy required will be drawn from your body's fat reserves and
weight will be lost
. This is
negative energy balance
Energy balance is achieved when:
Sometimes used to achieve and maintain energy balance.
Can you think of any supplements that may contribute to this?
You need to know;
Planning diets: appropriate for selected activity; appropriate for selected sports performer
Assessment of needs, eg weight gain, weight loss, muscle gain, fat gain, fat loss
Nutrition (macronutrients, micronutrients, fibre)
Food groups (grains, vegetables, fruits, oils, dairy, meat)
Sources and availability
Different activities require different dietary plans or strategies to optimise performance.
What different types of sporting activity can you think of that will require athletes to alter their diet plan strategies?
Fruit and Veg
Eat at least 5 portions of fruit and vegetables a day
Fresh, frozn, dried, tinned and juices (once a day) all count. Try to eat a variety. Try to avoid adding rich sources or butter to your vegetables and sugar or syrups to fruit. Make sure tinned fruit and veg don't have added salt and/or sugar.
Bread, rice, potatoes, pasta and other starchy foods
Eat lots of this food group
Breakfast cereal, oats, chapattis. Try to eat wholegrain versions where possible and avoid adding or cooing ion fat
Meat, fish, eggs, beans and other non-dairy sources of protein.
Eat moderate amounts and choose lower fat versions
Beans and pulses count as 1 portion towards 5 a day, 2 portions of fish a week with one oily fish. remove skin and visable fat from poultry
Milk and Dairy
Eat or drink moderate amounts and choose lower fat versions
Milk, cheese, yoghurt and fromage frais are included in this grouop. Swap whole milk for semi-skimmed. Choose low-fat versions of all dairy products, but remember that reduced fat cheeses aren't always low-fat so still kepp the portion small.
Foods high in fat and/or sugar
Eat just small amounts of these foods and drinks
This includes oils and spreading fats and sugar that you might add to food and drink. Also includes foods with high fat/sugar content such as mayonnaise, cream, chocolate, crisps, biscuits, pastries, cakes, ice cream, sugary soft drinks, sweets and honey. Choose unsaturated oils and spreading fats and avoid saturated fats like butter and lard.
Main role to build and repair tissue. It is also a secondary source of energy when carbohydrates and fat are limited.
Primary function of fats is to provide a concentrated source of energy, forming your body's largest potential energy store.
Form your body's most readily available source of energy and can be accessed rapidly. Two types of carbohydrates- simple and complex.
Write down everything you had to eat or drink yesterday!
Vital for specific metabolic functions and prevent particular deficiency diseases. They also support growth and the immune and nervous system functions, and some are involved in producing hormones.
Essential to health and form important components of your body such as bone, connective tissue, enzymes and hormones.
Essential and non essential;
Can you Identify in your food diary foods that contain the macronutrients?
Can you think of any other examples of foods that contain fats, proteins and carbohydrates?
What are the main sources for vitamins and minerals?
Can you name any vitamins and minerals?
Can you think of any current guidelines to do with our consumption of vitamins and minerals?
Research different sources of the nutrients we have looked at.
Can you identify the recommended amount of each?
Look back to your food diary, how does your intake compare to what is recommended?
Plan a healthy day's food diary using the information that you have gathered.
Research the key words from each section