Both saturated and unsaturated fats deserve a place in our diets. I grew up drinking raw milk and eating meals prepared with butter and palm oil. Someday, I’ll write a blog about a guy named Ancel Keys who almost single handedly (and quite wrongly) demonized saturated fats. Science simply does not support the idea that saturated fats cause heart disease; likewise, the low-fat food craze did nothing to lower heart disease rates.

What is true is that some cooking oils are better for you than others. You may want to avoid vegetable oils which tend to cause inflammation in the body, such as corn, sunflower, canola and soybean oils. Inflammation IS a risk factor for heart disease. Better-for-you oils include palm, olive, sesame, coconut, avocado and butter.  

But even the healthiest oils can go bad. I’m not just talking about cooking oil that smells awful after being used to fry fish. I’m talking about oils that are repeatedly heated at restaurants, a practice that may accelerate the formation of potentially carcinogenic compounds. What’s scary is that you can’t see, smell or taste these compounds. It’s another reason to avoid eating fried foods in restaurants. You don’t know how often they change their oil.

Just as toxic (yes, toxic!) are oils that are simply exposed to too much heat, even just one time. All oils have a smoke point. If you’ve ever heated oil to the point where it starts to smoke, then you’ve exceeded its smoke point. Once it gets too hot, the oil isn’t fit for consumption. Its molecular structure begins breaking down. It may form trans fats. It may damage your DNA.  

It’s even unhealthy to inhale smoke from overheated oils. That smoke may contain toxic fumes and harmful free radicals, which may elevate your risk of some chronic diseases including cancer. If a cooking oil starts to smoke, turn on your stove vent and open a window!

Use a variety of oils to take advantage of their individual nutritional benefits, and always match your oils with your cooking methods. Sesame oil and olive oil have relatively low smoke points, so I use them mostly for cold recipes such as salad dressings. For everyday cooking, I use a lot of butter. For curry and baking, my go-to oils are coconut and palm oil. Palm oil has one of the highest smoke points among cooking oils, and it’s versatile because it doesn’t have a strong flavor.

And always use fresh oils. That means buying only what you’ll use in 30 to 60 days. If you buy a big jug of olive oil at one of those big box stores, it could easily go rancid before you use it all.

And rancid = toxic. It’s not worth the risk.