Answer :
Lipids (fats) that are found in things such as butter, cream and cooking oil are important because they store energy so when all the carbohydrates run out energy, all the energy that is stored in the lipids (fats) can then be used. Fats acts as a store for extra energy.
Hope I helped :)
Fats are a source of energy well the main source of energy that your body uses. :)
