Fat facts

• A vegetable oil is an oil extracted from oilseeds or another plant source. Like all fats, vegetable oils are esters of glycerol and a varying blend of fatty acids, and are insoluble in water but soluble in organic solvents.
• Lipids that are solid at room temperature are called fats, while those that are liquid are called oils. Dietary fat is energy dense and supplies 9 calories per gram (compared to 4 calories per gram from carbohydrates and protein).
• Dietary fats are chemical compounds composed of carbon, hydrogen, and oxygen, and are found in a variety of foods, including animal products, seeds, nuts, and vegetables.
• Fatty acids are made up of carbon atoms arranged in chains of varying length, to which a variable number of hydrogen and oxygen atoms are joined.
• The structure of the carbon chain may include a double bond between the carbon atoms, resulting in unsaturation.
• Oils and fats have saturated, monounsaturated (MUFA), polyunsaturated (PUFA) and essential fatty acids (EFA).
• EFA - linoleic acid and alpha linolenic acid, are essential nutrients as it cannot be synthesized by the body on its own, but is required for many normal physiological processes. Arachidonic acid is sometimes considered essential but may be produced inside cells by the conversion of linoleic acid.
• Lipids aid in the absorption and transport of the fat-soluble vitamins (vitamin A, vitamin D, vitamin E, and vitamin K) and other fat-soluble nutrients.
• Fat improves the taste and feel of food and provides a sense of satiety.
• Food items such as sunflower oil, gingley oil, soybean oil, fish etc. containing PUFA though preferred, should be consumed in moderation, as PUFA is susceptible to oxidation, which is carcinogenic.
• If vegetable oils are cooked at high temperature, oxidation occurs rapidly.
• Substitute unsaturated fat - either PUFA or MUFA. Keep your fat calories to about 15-20% of your total calories.
• Margarine is made from vegetable oils by saturating the carbon bonds chemically, and this procedure robs the oil of its metabolic advantages.
• Fatty acids with unsaturated bonds may have one of two forms; cis and trans. The naturally occurring cis form only functions normally. The processing of vegetable oils to produce margarine and other cooking fats increases the trans forms of the same fatty acids, an undesirable result.
• Fresh vegetable oils (PUFA) are desirable. Because they are perishable foods, fresh oils should be stored under refrigeration. Light exposure increases fat oxidation; this can be reduced by packaging in black bottles or by freezing the oil. Eating too much of the wrong kinds of fat increases the risk of obesity, heart disease, and cancer. As a result, nutritionists and physicians often recommend that people reduce their total fat, saturated fat, and trans fat intake.