First, lipids are fats.
second, we need them for a variety of reasons- to create cushions for some organs (such as your eyes and skin), to allow proper hormone production (for example, testosterone cannot be produced by your body without fat), to allow the efficient storage of energy (rather than store energy as sugar or as protein, both of which take up a lot of space and can only be used for one thing, fat can be easily converted to either- or both- by your body and is slightly more compact than both also).
second, we need them for a variety of reasons- to create cushions for some organs (such as your eyes and skin), to allow proper hormone production (for example, testosterone cannot be produced by your body without fat), to allow the efficient storage of energy (rather than store energy as sugar or as protein, both of which take up a lot of space and can only be used for one thing, fat can be easily converted to either- or both- by your body and is slightly more compact than both also).
