FOOD

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FOOD
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FUNCTIONS OF FOOD

• 1. To provide energy
• 2. To provide material for growth

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TYPES OF FOOD

• Three types of food are required in large
  amounts in the daily diet
• Carbohydrates
• Proteins
• Fats

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TYPES OF FOOD

• Two other food types are required in smaller
  amounts
• Vitamins
• Minerals

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TYPES OF FOOD

• While water is not a type of food, it is an
  essential requirement in the diet

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CARBOHYDRATES

• The function of some types of carbohydrate is
• To provide energy
• For example
• SUGAR
• Found in

Honey
Fruit
Sweets
Cakes
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CARBOHYDRATES

• STARCH
• also provides energy
• Starch is found in

Potatoes
Pasta
Bread
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CARBOHYDRATES

• Another type of carbohydrate has the function of
  preventing constipation
• This type of carbohydrate is known as
• fibre
• Sources of fibre include

Vegetables
Wheatgerm
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FATS

• Fats have many functions in the body
• For example
• 1. To act as a store of energy
• 2. To insulate the body against heat loss

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FATS

• Good sources of fats in the diet include

Fatty meat
Milk
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PROTEINS

• Proteins have many functions in the body
• For example
• All enzymes are proteins
• Proteins also have structural functions
• Muscle is made from protein
• Bone contains a large amount of protein

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PROTEINS

• Good sources of proteins in the diet include
• Meat
• Milk
• Nuts

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MINERALS

• Minerals are required in small amounts
• Different minerals have different functions in
• the body

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MINERALS

• For example
• 1. Iron is required as a part of haemoglobin in
  the blood
• Good sources of iron in the diet are
• and dark green vegetables, for example

Liver
Spinach!!!
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MINERALS

• 2. Calcium is needed for healthy teeth and bones
• Good sources of calcium are

Milk
Cheese
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VITAMINS

• Vitamins are needed in only very small amounts
• The functions of vitamins are very varied

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VITAMINS

• For example
• Vitamin C is needed to prevent a disease called
  scurvy
• A good source of vitamin C is citrus fruit such
  as oranges and lemons

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VITAMINS

• Vitamin D is needed for the proper use of calcium
  in the body
• If the body is deficient in vitamin D, a disease
  called rickets results
• Vitamin D is formed by the action of sunlight in
  the skin
• Dairy products are a good source of vitamin D in
  the diet

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WATER

• The functions of water in the body include
• It is an excellent solvent and all chemical
  reactions in the cells take place in water
• It is used to transport substances in the blood
• It helps to remove wastes
• It helps to control body temperature

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TEST FOR SUGAR

• Add Benedicts solution
• Heat
• A brick red colour confirms the presence of
  reducing sugar

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TEST FOR STARCH

• Add iodine solution
• The appearance of a blue-black colour confirms
  the presence of starch

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TEST FOR FATS

• Rub the food into brown paper
• Allow to dry
• Hold up to the light
• The appearance of a translucent spot confirms the
  presence of fats

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TEST FOR PROTEIN

• Add sodium hydroxide solution
• Add copper sulfate solution
• The appearance of a violet colour confirms the
  presence of protein

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ENERGY IN FOOD

• The body uses carbohydrate for immediate energy
• The body uses fat as a long-term store of energy
• Protein is only used if all carbohydrate and fat
  have already been used up, i.e. if the body is
  starving
• Fats contain more energy than either
  carbohydrates or proteins

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ENERGY IN FOOD

• Energy is measured in units called kilojoules
• The amount of energy in a particular food product
  must be given on the label
• It is always expressed as the number of
  kilojoules contained per 100 grams of the food
  product

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ENERGY IN FOOD

• A demonstration that food contains energy can be
  given by using a burning piece of food to heat
  water
• The temperature of the water rises, showing that
  the chemical energy in the peanut is converted
  into heat energy

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BALANCED DIET

• A balanced diet is one that contains the correct
  amounts of all of the essential food types
• A diet must also be balanced in terms of
  energy
• The daily intake of energy should be the same as
  the amount of energy used

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FOOD PYRAMID

• A food pyramid gives suggestions as to how to
  select food to give a daily balanced diet
• Very little food from the top should be eaten
  daily
• Most food should come from the bottom level

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• THE END