Fats are one of the most common types of lipids. Lipids are a diverse group of molecules that include fats, steroids, and phospholipids. Fats, also known as triglycerides, are composed of glycerol and fatty acids. They are an important source of energy in the body and play a crucial role in insulation, protection of organs, and absorption of fat-soluble vitamins. Steroids, on the other hand, are a class of lipids that include hormones like testosterone and cholesterol. Carbohydrates and enzymes are not lipids.