Download What are Carbs?

WHAT ARE
CARBS?
Nutrients required by the body.
What do we want to know?
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What are they?
Why do we need them?
Are there different types?
What are the best type to eat?
What does GI stand for?
Carbohydrates
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Formed from the word carbo (meaning carbon) and
hydrate (meaning water)
Made up of carbon, hydrogen and oxygen
molecules (carbon and water)
Produced by plants
through photosynthesis
But most importantly:
CARBOHYDRATES
Provide the Body with ENERGY
They are one of the macronutrients needed by the
body in order to function properly.
Why else do we need carbs?
Not only do Carbohydrates provide energy
and heat for metabolism and activity, they
also:
 Regulate bowel movement (dietary fibre)
 Are Essential for brain function
 Regulate the use of fats and proteins
 Reserve proteins for primary function
 Glucose is the fuel of choice for active
muscles as it provides heat and energy
To the body
How does it give us ENERGY?
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When we eat, the body breaks down the
carbohydrates to make glucose which is then absorbed
into the bloodstream
Glucose = Fuel for our Bodies (1g CHO =16kJ)
A lot of carbohydrates also contain vitamins and
minerals that help keep us in tip-top shape and health
There are 3 types of Carbohydrates:
Monosaccharide
Disaccharide
Polysaccharide
Simple
Double
Complex
 Glucose – fruit
 Sucrose – sugar
(grapes)
cane
 Fructose – honey &  Maltose – cereals
fruits
 Lactose - milk
 Galactose – when
milk is digested
 Starch – fruits, vegies,
cereals
 Dextrin – formed from
starch (when bread is
toasted)
 Pectin – fruit (apples &
citrus fruits) also
known as hemicellulose
 Cellulose – fibre in
plants
 Glycogen – glucose
stored in liver
and muscles
Simple Carbohydrates
Have short chains of molecules so dissolve quickly
Eg. glucose, fructose, galactose
Foods include:
Cakes
Honey
Softdrink
Syrups
Lollies
Sugar
Jellies
Some fruits (grapes)
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Disaccharides (Double)
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When you have a joining of 2 monosaccharides
Eg. Sucrose, Maltose, Lactose
Foods Include:
Sugar cane
Cereals
Milk
Complex Carbohydrates
Have Long Chains of molecules and take longer to
dissolve
Eg. starch, dextrin, pectin, cellulose, glycogen
Foods include:
Pasta
Bread
Grains/Cereals
Fruits and vegetables
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How much do we need?
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Medical experts say that 45 - 60% of our diet
should be made up of carbohydrates
Average intake for a teenager should be about
8700 kilojoules per day
So, 8700 x 60 % = 5220 kilojoules
1 gram of carbohydrates = 16 kilojoules
So, the RDI (Recommended Daily Intake) is
approximately 310g of carbohydrates per day
Too much or not enough?
Excess
• Overweight & obesity
because excess glucose in
the body is stored as fat
• Diabetes (excess sugar in
the blood)
Deficiency
• Weight loss
• Starvation
• Fatigue
• Constipation
How do I get enough?
To help get the right amount of carbohydrates in your
diet, try to include 2 serves at each meal.
An example of a serve is:
2 slices of bread
1 cup cooked rice
1 1/3 cups cereal
1 medium piece of fruit
1 tub of low fat yoghurt
250ml glass low fat milk
Remember, a balanced diet is a healthy diet!!!
How do I know how many
carbohydrates a food contains?
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There is lots of information around: in books, on the
internet, health practitioners
All packaged foods must have labels to let us know
what they contain
Let’s have a look at a few
common foods and the
carbohydrates they
contain
Basic Foods
We could use Food Composition tables to analyse our diets.
Food
Serving size
Carbohydrates
1 medium
33g
1 tablespoon
17g
Ice cream (soft serve)
1 cup
22g
Corn Flakes
1 cup
24g
Apple
1 medium
19g
Banana
1 medium
27g
Grapes
1 cup
16g
Orange Juice
1 cup
33g
Spaghetti
1 cup
40g
Bread
1 slice
16g
Potato (boiled)
Honey
What is GI?
A ranking given to food that describes how quickly
the carbohydrates they contain will be digested
(changed to glucose) and absorbed into our bodies
Called the
GLYCAEMIC INDEX
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High GI foods are digested and absorbed quickly
Low GI foods are digested and absorbed slowly
Low V’s High
Low GI Foods
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Keep you feeling full for
longer as they provide a
gradual supply of energy
Helps keep blood glucose
levels stable
May help to prevent some
diseases
High GI Foods
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Used when high energy
levels are needed for
shorter bursts
Eg. athletes, sports people
body builders
Low GI Foods
High GI Foods
Wholegrain bread
Pasta
Oats
Apples, apricots and oranges
Yoghurt and milk
Dried beans
Lentils
Kidney beans
Rolled oats
White and wholemeal bread
Processed cereals
Short grain rice
Potato
Most cracker biscuits
Watermelon
Lollies, cakes etc
Dietary Fibre
Another kind of Carbohydrate
As if the humble Carbohydrate didn’t already have a big
enough job!!!!
It also provides our diet with fibre – a carbohydrate that only
comes from plant based foods (fruits, vegetables and
grains)
Fibre in food is tough and stringy and our bodies won’t break
it down completely so it helps to ‘regulate’ us
RDI of Fibre is 25 – 30g
Best Fibre options:
Wholemeal or Grain Breads, Bran, Fruit
and Vegetables, nuts, seeds, popcorn
Functions of Dietary Fibre
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Stimulates chewing and encourages saliva flow to
ensure healthy gums and teeth and more efficient
digestion
Inhibits the emptying process of the stomach,
therefore satisfying hunger for longer
Controls the rate of glucose absorption into the
blood by slowing down the digestion of nutrients
Softens faecal waste to ensure comfortable bowel
actions
Cooking with Carbohydrates
Sugars
 As a sweetener.
 As a preservative
 It provides food for yeast in bread
making.
 In cake making, it helps the fat to
entrap air, making cakes light.
 It colours food.
 Confectionery and sweets
 Cake decorating, icings and fillings.
 It softens gluten in cake making,
creating a lighter product.
 Syrups and glazes.
 Meringues – it strengthens the protein
in egg white, helping the mixture to
retain air.
Starch
 As a thickener in sauces, soups and
gravies.
 Found in cereals e.g. wheat may be
used in baking bread, cakes, etc.
 Found in root vegetables and potatoes.
 Found in foods such as pasta, bread
and rice, and forms the basis of a main
meal.
 Starch is hygroscopic; it absorbs
moisture from the air and is added to
baking powder to keep it dry.
Pectin
 Pectin found in ripe fruit helps to set jams and jellies.
Effects of dry and moist cookery methods
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Dry heat of sugar causes caramelisation.
When boiled, sugar dissolves in water and then
becomes a syrup. As water evaporates it
caramelises and eventually burns.
Starch dissolves, swells and bursts when heated
in water/liquids.
Dry heat causes starch cells to burst e.g.
popcorn, pastry.
When dry heat is applied to starch shorter
chain polysaccharides are formed, these are
called dextrins (toasting).
Summary
Carbohydrates:
 provide the body with ENERGY
 good source of fibre
 good source of vitamins
 3 different types:
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Monosaccharide (simple/sugar)
Disaccharide (double)
Polysaccharide (complex/starch)
The Glycaemic Index tells us how long the ‘energy’
from carbohydrates will stay in our body