The subject of cooking oils is a bit of a minefield these days. In the past, when there was no such thing as cholesterol and heart disease and cancer was a rarity, people used natural saturated fats like lard, ghee, butter, tallow and coconut oil for cooking and baking. Then the highly refined and processed polyunsaturated oils entered the picture and for the past 50 or so years we have been subjected to so much misinformation, disinformation and flat out lies about their contribution to heart health, cholesterol levels and the like. And what do you know? Ever since we have been using these products, which have crept into everything, heart disease, cholesterol problems, cancer, diabetes and Alzheimer’s, to name but a few, have sky rocketed. This can’t just be a coincidence, can it?
The truth is that heating oils is seldom a good idea – there are very few fats that can take the heat, so to speak. Eating food cooked in heated refined oils is the worst thing you can do for your health. We were never meant to consume deep fried anything, so we recommend either avoiding the practice or limiting it. If you want to fry at high temperatures, then stir-fry so that it’s a quick affair.
The smoke point of an oil has traditionally been used as a marker for when an oil begins to break down and form harmful substances. When an oil is refined, it increases the smoke point. In theory that sounds great but the refining process itself uses excessively high heat and the hydrogenation moves the hydrogen atoms around to create what is little more than plastic fat with a much higher melting point. Polyunsaturated fats like corn and soy become oxidized (in other words they go rancid) during cooking. This produces free radicals that damage DNA.
The smoke point of an oil is not constant – the fresher the oil, the higher the smoke point and the longer you cook with it, the more the smoke point drops.
TAKE HOME TIPS:
Don’t allow oils to smoke
Don’t reuse oil
Don’t cook for longer than is absolutely necessary
Don’t heat oils that can’t withstand high temperatures