Almost all foods contain some fat. Even quintessential fat-free foods like carrots and lettuce contain small amounts of this nutrient. That's a testament to how important fats are for life. Fat provides a terrific source of energy as well as a great depot for storing it. It is an important part of cell membranes, helping govern what gets into cells and what comes out. The body uses cholesterol as the starting point to make estrogen, testosterone, vitamin D, and other vital compounds. Fats are also biologically active molecules that can influence how muscles respond to insulin's "open up for sugar" signal; different types of fats can also fire up or cool down inflammation.
