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Health, Fitness and Nutrition
PE Revision…read more

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Measures of Nutritional Stability
Basal Metabolic Rate (BMR):
"The rate at which a person uses energy to maintain the basic functions of the body".
Varies from person to person.
Depends on age, gender, height and weight.
The Harris Benedict equation factors in the amount of exercise you do to adjust your BMR.
Percentage body fat/body composition:
Body fat = "The proportion of body fat compared to lean tissue".
Body composition = "The percentage of body weight which is fat, muscle, bone and water".
People should find the energy intake that enables them to maintain their weight within the desirable
range for their height.
Any excess energy taken in daily is stored as fat.
On average, men have 10 ­ 20% body fat, and women have 15 ­ 25%.
The skinfold method estimates percentage body fat by measuring the thickness of skin at specific
locations around the body and compared to norm tables.
The bioelectrical impedance test involves entering your gender, age, height and weight into a device
that sends electrical signals around the body and tests the body's resistance against these signals.
Body Mass Index (BMI):
Indication of height to weight ratio.
A high BMI (30+) indicates obesity.
This is not the most accurate indicator of health for sportspeople because it doesn't take into account
fat/muscle content (muscle weighs more than fat so a rugby player may be considered obese when
they are not.)…read more

Slide 3

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The Seven Classes of Food
Carbohydrates:
Macronutrient.
Most important function is to provide energy ­ glucose for cells and tissues (respiration) is
mainly provided by carbs.
The carbohydrates in food are digested and converted to glucose which enters the blood. The
level of glucose in blood is carefully monitored and kept within narrow limits by the hormone
insulin.
Excess glucose may be stored as glycogen in the liver and in muscle ­ extra glucose is not
wasted.
Carbohydrate is the body's preferred source of energy at all levels of activity. If exercise uses up
the available glucose, then stored glycogen may be used for energy.
To replace the used glucose and glycogen, fat is converted into glucose.
Carbohydrates are compounds of carbon, hydrogen and oxygen.
The can be divided into three main groups:
Monosaccharides ­ simplest carbohydrate molecules (e.g. Glucose and fructose).
Disaccharides ­ sugars formed when two monosaccharides join together with the removal of
one molecule of water (e.g. Sucrose, lactose and maltose).
Polysaccharides ­ made up of many monosaccharide molecules
(usually glucose) joined together (e.g. starch, glycogen and cellulose).
Carbohydrates are also known as complex and simple
carbohydrates. Simple carbohydrates release energy quickly
(e.g. chocolate, biscuits) and complex carbohydrates release energy more
slowly (e.g. porridge) as they are harder to break down.…read more

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The Seven Classes of Food
Fat:
Macronutrient.
Composed of carbon, hydrogen and oxygen, and the building blocks for fat are fatty acids and glycerol.
4 Types of fat:
Saturated fat = If the fatty acid has all the hydrogen atoms it can hold it is said to be saturated.
Unsaturated fat = If some of the hydrogen atoms are missing and have been replaced by a double bond
between the carbon atoms, then the fatty acid is said to be unsaturated.
Monounsaturated fat = one double bond.
Polyunsaturated fat = more than one double bond.
Three fatty acids combine with one molecule of glycerol to form a triglyceride (simple fat).
The body can make all the fatty acids it needs apart from two essential fatty acids which must be
supplied in the diet.
The nature of fat depends on the types of fatty acids which make up the triglyceride ­ `saturated' fats are
solid at room temperature and tend to be derived from animal sources, whereas most unsaturated fats
are liquid at room temperature and are usually vegetable fats (also called oils).
Fat is a concentrated source of energy ­ it provides more than double the energy provided by
carbohydrates and is also a carrier for fat soluble vitamins (A, D, E, K).
Fat is only used as an energy source at rest and during low intensity exercise because it requires much
more oxygen to break it down than the equivalent amount of carbohydrate.
Hence, when exercising at high intensity and oxygen supply is low, fat cannot be
efficiently broken down and so carbohydrate is used as the energy source.
A high fat intake (especially saturated fat) has been associated with a
raised blood cholesterol level, which is one of the risk factors for coronary
heart disease.…read more

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The Seven Classes of Food
Protein
The main sources of protein include meat, fish, eggs, milk, cheese, cereals and cereal products, nuts and
pulses.
The building blocks of protein are amino acids (compounds containing carbon, hydrogen, oxygen and
nitrogen).
There are about 20 different amino acids commonly found in plant and animal proteins. After a protein
is eaten it is broken down by digestion into amino acids, which are absorbed and used to make other
proteins in the body.
The human body is able to make some amino acids itself ­ these are known as non-essential amino
acids. However, it is not possible to do this for every amino acid, so a certain number must be supplied
by the diet (essential amino acids).
Protein is necessary for the growth and repair of body tissues and is a minor source of energy. Athletes
who are training in strength/power type activities will be repairing and developing muscle tissue, and
will therefore require sufficient protein in their diet.…read more

Slide 6

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The Seven Classes of Food
Fibre
Dietary fibre compromises the edible parts of plants that are not broken down
and absorbed in the small intestine.
Most people do not eat enough dietary fibre. The major sources of dietary fibre
are whole-grain and high-fibre breakfast cereals.
Dietary fibre can act as a bulking agent and help prevent constipation. They can
also help reduce blood cholesterol levels and help control blood glucose levels.…read more

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