In humans we need Carbohydrates, Proteins, Fat, Fibre, Vitamins, Minerals and Water. an example of why we need these are carbohydrates which break down into glucose for energy, protein for growth and development fat for insulation as well as energy fibre for digestion Vitamins and minerals help convert food into energy as well as calcium which (through ossification) develops and grows bones and water is essential for basic cell functions I hope this helps somewhat ^^;
