Nutrition

• Balanced diet


  The correct amount of each food, not simply 'enough' food
• Main food groups in a balanced diet


  • Carbohydrates
  • Fats
  • Protein
  • Fibre
  • Minerals
  • Vitamins
  • Water
• Carbohydrates


  Required by our bodies as a source of energy. Examples: pasta, potatoes, rice
• Fats


  Needed to insulate our bodies and to make cell membranes. They also contain fat-soluble vitamins. Examples: cheese, butter, oils, margarine
• Protein


  Required for growth and repair. Examples: meat, fish, eggs, cheese
• Fibre


  Allows the muscles in our intestines to move material along (peristalsis) and prevents constipation. Not digested in our diet. Examples: wholemeal products, fruit, vegetables
• Minerals


  Different elements, e.g. iron used to make haemoglobin
• Vitamins


  Different structures, e.g. vitamin C prevents scurvy
• Water


  All chemical reactions take place in water
• The exact amount of each substance needed in a balanced diet will vary depending on age, sex, and activity level
• There are differences in protein needs between sexes due to growth spurts and periods in girls
• First class proteins


  Proteins from animals that contain more variety of amino acids compared to plant proteins
• Some people's diets may be influenced by factors other than daily requirements, such as being vegetarian/vegan or following religious dietary requirements
• Some people may have to avoid certain foods to prevent them becoming ill
• Biuret test for protein

  Add food to copper sulphate solution with sodium hydroxide, light blue changes to purple if proteins are present
• Alcohol emulsion test for fat


  Mix food with water and ethanol, white emulsion (tiny fat droplets in water) indicates presence of fat
• Iodine test for starch

  Add iodine to food, it will go blue/black if starch is present
• Overweight


  Having extra body weight from muscle, bone, fat, and/or water
• Obesity


  Having a high amount of extra body fat
• Body mass index (BMI)

  A measure of body fat based on height and weight that applies to adult men and women
• Factors contributing to weight


  • Environment
  • Family genetics
  • Metabolism
  • Lifestyle