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.
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? • 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
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)
Disaccharides (Double) • 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
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
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 the carbohydrates they contain
Basic Foods 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 Low GI Foods High GI Foods • 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
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
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