Fat
A molecule of dietary fat typically consists of several fatty acids (containing long chains of carbon and hydrogen atoms), bonded to a glycerol. They are typically found as triglycerides (three fatty acids attached to one glycerol backbone). Fats may be classified as saturated or unsaturated depending on the detailed structure of the fatty acids involved. Saturated fats have all of the carbon atoms in their fatty acid chains bonded to hydrogen atoms, whereas unsaturated fats have some of these carbon atoms double-bonded, so their molecules have relatively fewer hydrogen atoms than a saturated fatty acid of the same length. Unsaturated fats may be further classified as monounsaturated (one double-bond) or polyunsaturated (many double-bonds). Furthermore, depending on the location of the double-bond in the fatty acid chain, unsaturated fatty acids are classified as omega-3 or omega-6 fatty acids. Trans fats are a type of unsaturated fat with trans-isomer bonds; these are rare in nature and in foods from natural sources; they are typically created in an industrial process called (partial) hydrogenation.
Many studies have shown that unsaturated fats, particularly monounsaturated fats, are best in the human diet. Saturated fats, typically from animal sources, are next, while trans fats are to be avoided. Saturated and some trans fats are typically solid at room temperature (such as butter or lard), while unsaturated fats are typically liquids (such as olive oil or flaxseed oil). Trans fats are very rare in nature, but have properties useful in the food processing industry, such as rancid resistance.
Read more about this topic: Animal Nutrition
Famous quotes containing the word fat:
“How can I go on, I cannot. Oh just let me flop down flat on the road like a big fat jelly out of bowl and never move again!”
—Samuel Beckett (1906–1989)
“O why do you walk through the fields in gloves,
Missing so much and so much?
O fat white woman whom nobody loves,
Why do you walk through the fields in gloves,
When the grass is soft as the breast of doves
And shivering sweet to the touch?”
—Frances Cornford (1886–1960)
“Upscale people are fixated with food simply because they are now able to eat so much of it without getting fat, and the reason they don’t get fat is that they maintain a profligate level of calorie expenditure. The very same people whose evenings begin with melted goat’s cheese ... get up at dawn to run, break for a mid-morning aerobics class, and watch the evening news while racing on a stationary bicycle.”
—Barbara Ehrenreich (b. 1941)