Fat

Fat (dufan, baruur) is a class of organic compounds and one of three major macronutrients—fat, protein, and carbohydrates. Chemically, most dietary fats are triglycerides: molecules composed of glycerol bonded to three fatty acids. Fat does not dissolve in water and is less dense than it, which is why it floats when mixed in.

When consumed, fat provides more energy than an equal amount of carbohydrate—roughly twice as much. The body stores excess fat in adipose tissue (fat tissue), which it uses for energy, insulation, and protection of internal organs.

Types of Fatty Acids

Fatty acids are classified by the arrangement of carbon bonds. Saturated fats have no double bonds; they are typically solid at room temperature and are found in butter, meat, and coconut oil. Unsaturated fats have one or more double bonds; they are typically liquid and are found in olive oil, nuts, and fish. Trans fats are partly produced through the industrial process of hydrogenation.

Role in the Body

Fat is not merely an energy store. It is necessary for the absorption of fat-soluble vitamins—A, D, E, and K. It is also essential for building cell membranes and producing certain hormones. Two fatty acids—linoleic and alpha-linolenic—cannot be synthesized by the body and must be obtained from food; these are called essential fatty acids.

Sources and Use

Fat is obtained from animals (meat, milk, butter, ghee) and plants (seed and nut oils, nuts, coconut oil, olive oil). In food preparation, fat increases the caloric density of food, carries flavor compounds, and alters the texture that food has in the mouth. Food manufacturers use it to extend shelf life.