What is the fine-grained topic of the following text: Fat, although shunned by some, is highly concentrated energy source (double that of protein and carbohydrates) supplying the body with fat soluble vitamins A, D, E, and K.
Fat is also a necessary component of all cell membranes, nerve covering, digestive secretions and most importantly, hormone production. Only return the topic.
The Importance and Functions of Fat in the Human Body