macronutrients

• proteins are useful for growth, repairing body cells and tissues, produce enzymes for digestion, producing hormones, provides a secondary source of energy
• sources of protein 


  animal source: meat, fish, dairy foods, eggs

  plant source: peas, beans, nuts, grains

  other sources: tofu, soya
• proteins are made up of amino acids. amino acids are linked together by peptide bonds
• high biological value (HBV) - contains all 8 essential amino acids that must come from our diet
• low biological value (LBV) - these do not contain all 8 essential amino acids there are 12 non essential amino acids that are produced by the body
• there are 2 types of carbohydrates - starches and sugars

  • sugars - simple carbohydrate, enter bloodstream rapidly after eaten, raise blood sugar levels very quick, sources: sweets, biscuits, shakes, honey

  • starches - complex carbohydrates, keep blood sugar levels constant, enter blood stream very slowly, sources: bread, rice, pasta, cereal
• functions of carbohydrates

  • the body needs carbohydrates for energy

  • provides the body with fibre (whole grain - cereal, rice, bread)

  • carbohydrates allow proteins to be used for growth and repair
• there are 2 types of fats

  • saturated fats - solid at room temperature (e.g. butter), come from animal sources therefore tend to be more unhealthy, sources: red meats, dairy products

  •unsaturated fats - liquid at room temperature, come from plant sources so they are healthier for you, sources: margarine, vegetable oil, oily fish, nuts, avocado, olives
• unsaturated fats

  • poly-saturated fats - have more than one double bond (‘poly’) sources: margarine, vegetable oil, oily fish (e.g. mackerel)

  • mono-saturated fats - have 1 double bond (‘mono’) source: nuts, nut oil, avocado, olives, olive oil