The four main types of lipids are fats and oils (triglycerides), phospholipids, waxes, and steroids.
Triglycerides - They make up more than 95 percent of lipids in the diet and are commonly found in fried foods, vegetable oil, butter, whole milk, cheese, cream cheese, and some meats.
Phospholipids - They make up only about 2 percent of dietary lipids. They are water-soluble and are found in both plants and animals.
Steroids - They are the least common type of lipid. Cholesterol is the most common steroid. It is an important component of the cell membrane and is required for the synthesis of sex hormones, vitamin D, and bile salts.
Waxes - Wax covers the feathers of some aquatic birds and the leaf surfaces of some plants. Because of the hydrophobic nature of waxes, they prevent water from sticking on the surface.