The 2 main groups of carbohydrates are sugars and starches.
The main functions is to provide energy in the diet.
Too much and little exercise= overweight.
Classified according to their structure and divided into monosaccharides, disaccharides and polysaccharides according to the size of the molecule.
The 3 monosaccharides are:
Glucose- occurs naturally in fruit and plant juices
Fructose- occurs naturally in some fruit and veg and is found in honey (the sweetest form)
Galactose- found with glucose as lactose- the sugar in milk
Consists of 2 monosaccharide molecules joined together.
Sucrose- occurs naturally in sugar cane and sugar beet and is also found in fruit and veg
Lactose- sugar present in milk
Maltose- forms when grain is germinated for the production of malt liquors e.g beer
Made up of many monosaccharide molecules joined together (also known as complex carbs).
Starch- the main food reserve in plants and consists of many glucose molecules
Glycogen- made from glucose by animals rather than plants
Sources of carbohydrates
Starchy foods such as bread, pasta, rice, potatoes and cereal are a good source of carbs.
Starches account for almost 60% of the total carb intake in the average British diet.
Food and drink containing sugars such as the sugar found in milk, fruit, veg and jam are also good sources of carbs.
Sugars account for almost 40% of the total carb intake in the average British diet.
Average daily intake for men is 272g and 193g for women.
Functions of carbohydrates
Provides a source of energy. 1 gram of carbohydrate provides 16KJ of energy.
Acts as a protein sparer because carbs provide energy so therefore protein can be used as it's primary fuction e.g growth and repair of cells.
Eating many sugary foods between meals is associated with increased tooth decay.
The 1991 COMA report made recommendations regarding sugar consumption using the terms intrinsic and non-intrinsic sugars which led to some maufacturers using these terms on food labels.
Intrinsic and non-intrinsic sugars
Intrinsic- enclosed in the cell and can be found in fruits and vegetables
Non-intrinsic- located within the cellular structure and can be divided into: milk sugars (occurs in milk and milk products) and non-milk extrinsic sugars (NMES) e.g fruit juice and honey