carbohydrates: glucose is used to produce energy (ATP)/if too much is eaten stored as glycogen
proteins: growth + repair of tissues
Fats: store of energy + thermal insulation
Water: essential part of many body functions and processes
Iron (minerals): production of haemoglobin
haemoglobin = found in red blood cells
Vitamin c = mantains healthy tissue
Fibre = provides bulk in the digestive system (prevents diarrhea)
Sugar = added for taste + to increase shelf life --> type 2 diabetes , obesity + tooth decay
Fat = increase taste --> obesity + heart disease
Salt = taste / shelf life --> high blood pressure
Practical:
weigh 1g of food
record starting temp of water
ignite food with bunsen burner + hold under tube until fully burned
record final temp of water ---> find difference
use: equation
Limitation of practical = method under-estimates energy content ---> heat energy can easily escape as it is not insulated + food may not completley burn
improvement of prac = insulate apparatus with foil + use dataloggers
fats = 2x energy of carbohydrates + proteins
hazards of prac =
burning food is hot - hot grease could drip on you - control = hold with tongs
boiling tube is hot - could burn hand - heatproof gloves
independent variable = change
dependent variable = measure
Control variable = factors to ensure accurate results