When I make a stir fry, roast veggies or use any method of heat to cook something, I always start with a splash of olive oil in the pan so whatever I’m cooking doesn’t stick. I use olive oil because I’ve always thought it is a healthy oil. Olive oil is healthy but it really depends on how you’re using it and the quality of the oil.
There are many varieties of olive oil on the market. Labels such as ‘extra virgin’, ‘cold pressed’ and ‘organic’ are key words found on many of those bottles. I can go to Costco and pick up a litre of extra virgin olive oil for about $10, or the local market where it has some generic brand name olive oil is on sale for $8. On the other end of the spectrum, I can go to the Olive Oil Company or Whole Foods where the same size bottle is triple the price. So what’s the difference? Does it matter?
Olive oil is a monounsaturated fat. It’s liquid at room temperature (unlike a saturated fat, like coconut oil, that is solid at room temperature). One of the characteristics of monounsaturated fats is that they have one double bond in their molecular structure. Coconut oil, for example, has no double bonds (just like any other saturated fat). The more double bonds an unsaturated fat has, the less stable it is. The stability of a fat is valued when a company is mass producing it because it will have a longer shelf life. For example, fresh olive oil, when exposed to heat, light or oxygen, will go rancid faster. So how is one way that companies can produce olive oil and ensure that it doesn’t go rancid when it’s being shipped and shelved for long periods of time? Hydrogenation.
Hydrogenation is a process where high heat, high pressure and hydrogen are used to saturate or partially saturate oil. The result of this transformation produces a semi-solid fat that is less likely to go rancid. The problem with this process is that partially-hydrogenated fat becomes trans-fats. We don’t want those – ingesting trans-fats can have significant health implications for you and I, including raising cholesterol and increasing our risk of heart disease, among other things. Studies have linked increased consumption of trans-fats to Alzheimer’s disease, cancer, diabetes, obesity and mood disorders.
A good quality extra-virgin olive oil should not be hydrogenated, and should be pure olive oil (no fillers). So now that you’re convinced on buying the good quality $20 bottle of olive oil produced locally, I’m also going to break some bad news. Olive oil should only be used in cooking if you’re cooking with a low temperature. Remember when I said that olive oil will go rancid when it’s exposed to light, heat and oxygen? Well, cooking at high temperatures (like in a frying pan, or roasting vegetables in the oven) will impact the quality of the olive oil by altering the chemical structure of the oil to the point that it becomes toxic. So we spend money on the good quality, only to negate those good nutrients by heating it. Olive oil is best used to top off your salads in a salad dressing (and when you buy the good quality stuff you’ll see why I sometimes use only olive oil in salad) or other uses that don’t involve cooking. Store it out of direct light and keep the lid on!
Before wrapping this topic up, I’ll answer the natural next question that you probably thought about – so what do I cook with? Saturated fats. Coconut oil, ghee, or butter are the best because they’re the most stable oils.
There’s so much more on this topic – is coconut oil a good saturated fat? Are all fats created equal? What fats should I be eating? – that I will tackle in future posts. If you have any questions, feel free to give me a shout and I will do my best to answer them!