Saturated fat; Diet - fat; Polyunsaturated fat; Monounsaturated fat; Lipids
Definition
Fats are organic compounds that are made up of carbon, hydrogen, and oxygen; they are the most concentrated source of energy in foods. Fats belong to a group of substances called lipids. Fats come in liquid or solid form. All fats are combinations of saturated and unsaturated fatty acids. Fats can be called very saturated or very unsaturated depending on their proportions.
Food sources
Saturated fats are found in foods from both animal and vegetable sources. Animal sources include meat, poultry, and whole-milk dairy products such as cheese, milk, ice cream, cream, butter, and lard. Vegetable sources -- including coconut, palm kernel, and palm oils -- are also high in saturated fat.
Unsaturated fat is a type of fat that is usually liquid at refrigerator temperature. Monounsaturated and polyunsaturated fat are two kinds of unsaturated fat. Monounsaturated fat is found in large amounts in foods from plants, including olive oil, peanut, avocado, and canola oil (from rapeseed). It is a slightly unsaturated fat. Polyunsaturated fat is highly unsaturated fat that is found in large amounts in foods from plants, including safflower, sunflower, corn, and soybean oil. Omega-three fatty acid (fish oil) is a polyunsaturated fat found in seafood, particularly fish that is fatty. Seafood is lower in saturated fat than meat.
Functions
Fat is one of the three nutrients (along with protein and carbohydrates) that supply calories to the body. Fat provides 9 Calories per gram, more than twice the number provided by carbohydrates or protein.
Fat is essential for the proper functioning of the body. Fats provide the "essential" fatty acids, which are not made by the body and must be obtained from food. Linoleic acid is the most important essential fatty acid, especially for the growth and development of infants. Fatty acids provide the raw materials that help in the control of blood pressure, blood clotting, inflammation, and other body functions.
Fat serves as the storage substance for the body’s extra calories. It fills the fat cells (adipose tissue) that help insulate the body. Fats are also an important energy source. When the body has used up the calories from carbohydrate, which occurs after the first 20 minutes of exercise, it begins to depend on the calories from fat.
Healthy skin and hair are maintained by fat. Fat helps in the absorption, and transport through the bloodstream of the fat-soluble vitamins A, D, E, and K.
Recommendations Return to top
Approximately 40% of the calories consumed in the United States are from fat. Current recommendations for fat intake are different depending on preexisting medical conditions and cholesterol level. In general, for most people, less than 30% of total daily calories should come from fat. Saturated fat should be limited to less than 10% of the total calories for the day. The remainder of the day’s fat intake should be equal amounts of polyunsaturated and monounsaturated fat.
Children under two years of age should NOT be on a fat restricted diet because cholesterol and fat are thought to be important nutrients for brain development.
It is important to read the nutrition lables and be aware of the amount of different types of fat contained in food. It is recommended that everyone over 20 have their cholesterol checked. Talk to your health care provider about how to cut down of your fat intake and to have your cholesterol checked.
Side effects
Eating too much saturated fat is one of the major risk factors for heart disease. A diet high in saturated fat causes a soft, waxy substance called cholesterol to build up in the arteries. Too much fat also increases the risk of heart disease because of its high calorie content, which increases the chance of becoming obese (another risk factor for heart disease and some types of cancer).
A large intake of polyunsaturated fat may increase the risk for some types of cancer. Reducing daily fat intake is not a guarantee against developing cancer or heart disease, but it does help reduce the risk factors.