Indian cooking requires extensive use of oil. Cooking instructions often say the oil should separate from the masala. Itis sometimes even poured ontop of a dish after cooking. Mostly, however, we tend to deep fry or sauté the ingredients.

Oil now has a bad reputation and is blamed for clogging arteries, producing hypertension and causing heart disease. Also, traditional hydrogenated oils like vanaspati have fallen into disfavour.

It is not possible to avoid oil altogether. It is present naturally in foods like fish, meat and even vegetables. Also, oil is needed to absorb essential fat-soluble vitamins A, D, E and K. It provides a concentrated, compressed source of energy for physical activity.

An overwhelming variety of oils is available in the market. There are vegetable oils — hydrogenated, cold pressed or refined; animal-based oils like ghee and butter; saturated vegetable oils such as palm oil; and hydrogenated oils like vanaspati. They all add to the unique taste of different dishes.

Cold-pressed oil is extracted by pressing the seeds. No chemicals are added and no heat is used. The oil retains its flavour, is healthy and contains omega-3 fatty acids and antioxidants. These antioxidants scavenge dangerous free radicals and promote their decomposition.

Refined oils are made by heating the oil seeds and then adding chemical solvents to make the extracted oil clear and attractive and to increase its shelf life. The process destroys much of the healthy omega-3 fatty acids and antioxidants. However, it also removes some dangerous chemicals.

For example, the peanut crop may be contaminated with a fungus that releases a poison called aflatoxin. If this is ingested, it causes nausea, vomiting and abdominal pain. Sufficient prolonged intake causes cirrhosis and even cancer of the liver.

All oils have a range of smoke points or temperatures at which they are no longer stable. It is different for different types of oil. If heated above this temperature, the oil begins to break down, oxidise and release compounds with negative health consequences. They can cause cellular damage and disease development. That can aggravate many chronic health problems, such as cardiovascular and inflammatory disease, cataracts and cancer. Heating or reusing oil (common in street food) above their smoke point also releases acrolein. It gives the food an unpleasant burnt flavour. It also causes coughing, wheezing, shortness of breath, chest pain and lung disease.

Different types of oils contain trace amounts of distinctive beneficial products. It is best to mix the different types of oils. Use around 20 per cent of cold pressed oil and mix it with equal volumes of sesame, ground nut, rice bran, coconut and mustard oil. Olive oil is healthy but expensive.

In a healthy diet, 30 per cent of the total calories for the day should be from fat. If you are on a 2,000 calories per day diet, then 600 calories should be from oils. One ml of oil provides around nine calories, so a person needs only two tablespoons or 60ml of oil per day. An easy calculation is half a litre of oil per month for each member of the family. A family of four requires two litres of oil. This does not take into account hidden oils present in snacks, pickles or used in mayonnaise and salad dressing.

When selecting a cooking oil, factors to be considered are smoke point, flavour and nutritional content. Remember, oils can vary in their fat composition and nutritional benefits, so choose oils that align with your taste and dietary preferences, and help maintain health goals.