WHAT ARE CARBS? Nutrients required by the body.
WHAT ARE CARBS?
Nutrients required by the body.
What do we want to know?
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
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.
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
Why else do we need carbs?
How does it give us ENERGY? 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
SimpleDisaccharide
DoublePolysaccharide
Complex
Glucose – fruit (grapes)
Fructose – honey & fruits
Galactose – when milk is digested
Sucrose – sugar cane
Maltose – cereals Lactose - milk
Starch – fruits, vegies, cereals
Dextrin – formed from starch (when bread is toasted)
Pectin – fruit (apples & citrus fruits) also known as hemi-cellulose
Cellulose – fibre in plants
Glycogen – glucose stored in liver
and muscles
Simple Carbohydrates
Have short chains of molecules so dissolve quickly
Eg. glucose, fructose, galactoseFoods include:Cakes HoneySoftdrink SyrupsLollies SugarJelliesSome fruits (grapes)
Disaccharides (Double)
When you have a joining of 2 monosaccharides
Eg. Sucrose, Maltose, LactoseFoods Include:Sugar caneCerealsMilk
Complex Carbohydrates
Have Long Chains of molecules and take longer to dissolve
Eg. starch, dextrin, pectin, cellulose, glycogen
Foods include:PastaBreadGrains/CerealsFruits and vegetables
How much do we need?
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
Excess Deficiency
• Overweight & obesity because excess glucose in the body is stored as fat• Diabetes (excess sugar in the blood)
• Weight loss• Starvation• Fatigue• Constipation
Too much or not enough?
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? 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 thecarbohydrates they contain
Basic Foods
Food Serving size Carbohydrates
Potato (boiled) 1 medium 33g
Honey 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
We could use Food Composition tables to analyse our diets.
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
High GI foods are digested and absorbed quickly
Low GI foods are digested and absorbed slowly
Low V’s High
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
Used when high energy levels are needed for shorter bursts
Eg. athletes, sports people
body builders
Low GI Foods High GI Foods
Low GI Foods High GI Foods
Wholegrain breadPastaOats
Apples, apricots and oranges
Yoghurt and milkDried beans
LentilsKidney beansRolled oats
White and wholemeal bread
Processed cerealsShort grain rice
PotatoMost cracker biscuits
WatermelonLollies, cakes etc
Dietary FibreAnother 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
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 Starch 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.
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
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:
• Monosaccharide (simple/sugar)• Disaccharide (double)• Polysaccharide (complex/starch)
The Glycaemic Index tells us how long the ‘energy’ from carbohydrates will stay in our body