Physical Education · Ch 5 — Sports and Nutrition
Fats (Lipids)
Fats (Lipids)
5.2.3 Fats (Lipids)
Lipids, or dietary fats, is a broad term covering both oils and fats. Oils are liquid at room temperature and fats are solid, and it is the type of fatty acids present that makes a lipid liquid or solid.
Fatty acids are the building blocks of fats and oils. They are classified as saturated or unsaturated according to the number of double bonds in their chemical structure:
- Saturated fatty acids (SFA) — no double bond
- Monounsaturated fatty acids (MUFA) — one double bond
- Polyunsaturated fatty acids (PUFA) — more than one double bond
When the proportion of saturated fatty acids is higher, the fat is solid at room temperature; when unsaturated fatty acids (MUFA or PUFA) predominate, the lipid is liquid and is called an oil.
Saturated fats, also called animal fats, are linked to increased health risks: they raise total and LDL (“bad”) cholesterol and so increase the risk of heart disease. Their intake is recommended to be kept below 7% of total calories. The main sources are desi ghee, butter, cheese, cream, red meats, baked products and other full-fat dairy products; coconut and palm oils also contain saturated fats.
Unsaturated fats — the MUFA and PUFA — help lower blood cholesterol and reduce heart-disease risk when they replace saturated fats. Canola, olive, peanut, palmolein, rice-bran and til (sesame) oils, and nuts such as walnuts, are rich in monounsaturated fats. Sources of PUFA include vegetable oils, mustard, soybean, corn, safflower and sunflower oils, and flaxseed.
Dietary fat comes from both visible and invisible sources. Visible sources are ghee, butter and cooking oil; invisible sources include nuts, cereals, pulses, milk, eggs and meat. Invisible fat contributes significantly to the total fat and essential fatty acid content of the diet, depending on the foods eaten. Total fat (visible + invisible) should provide 15–30% of the total calories required, and the contribution of visible fat should be restricted to 20–30 g per day, depending on the individual's level of physical activity.
Do you know? — Fats, cholesterol and trans fats
For adults, total fat intake should be about 20–30% of calories to meet energy and nutritional needs while minimising the risk of chronic disease. Saturated fat should be less than 7% of calories, dietary cholesterol less than 300 mg/day, and trans-fatty acid intake as low as possible. Certain fatty acids (MUFA and PUFA) are encouraged for their positive health effects — for example oils from vegetable sources, nuts, rice bran and fish. An ideal quality fat maintains a balance between SFA, MUFA and PUFA, which can be achieved by combining oils (for example, mustard oil with sunflower oil, or safflower oil with palm oil).
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