Ask the dietitian: How to choose the right oil for different cooking temperatures

November 13, 2018 Katie Woeckener RD, CDE

Many of us are health conscious about using the healthiest oils for cooking. But often, without knowing it, you can make a good, healthy oil into an unhealthy one if cooking it at the wrong temperature. So you want to be sure you use the right oil for the correct cooking method to optimize your health.

For high temperature cooking, such as grilling, select cooking oils with a high smoke point >375°F.  For low-temperature cooking such as sautéing, or adding to dishes and salad dressings, choose oils with lower smoke points (<300°F)  or higher omega-3 fatty acids. Omega-3 fats are known for their anti-inflammatory action. Both omega-6 and omega-3 fatty acids found in oils are important for health, but a greater proportion of the omega-3 fatty acids are desirable for reducing the risk for heart disease.

Example: Flaxseed oil is 1:4 (omega-6:omega-3 ratio), which is desirable for reducing inflammation compared to corn oil that is 83:1.

The smoke point is important to pay attention to when you are choosing your oil in cooking. The smoking point is the temperature at which a heated fat or oil starts to break down and produces smoke, giving an unpleasant smell and taste to food. At that point, the fat is breaking down and can produce potentially toxic compounds. This is why you should not cook with a low smoke point oil (<300°F) at a high temperature.  Doing so can change your healthy oil, into something not so good for your body.

A high smoke point is typically one above 375°F, as that's the temperature you usually fry at. Be sure you choose the fat that has a smoke point above the temperature you will be cooking.

Best oils for salad dressings:

  • Extra virgin olive oil
  • Flaxseed oil
  • Grapeseed oil
  • Hemp seed oil

Best oils for sautéing (212-300°F):

  • Avocado oil
  • Coconut oil
  • Olive oil
  • Sesame oil
  • Sunflower seed oil

Best oils for baking (at or <350°F):

  • Avocado oil
  • Olive oil
  • Coconut oil

Best oils for grilling and frying (>375°F):

  • Avocado oil
  • Canola/Corn/Vegetable oil
  • Light olive oil (refined)
  • Peanut oil
  • Sesame oil

* = Good source of omega-3

Storing Oils:

Most oils will last for 1 year when stored properly, with the exception of coconut oil and peanut oil which will last for 2 years.

Oils should be stored in a cool, dry, dark cupboard, away from the heat and light.

Best oils to refrigerate: avocado oil, flaxseed oil, grapeseed oil, sesame oil.

If storing in your kitchen, choose a spot that’s away from the oven and will not come in contact with heat.

The best temperature for storing oil is typically between 57-70°F.

Key points:

Flaxseed oil and macadamia nut oil are highest in omega-3 fatty acids which is beneficial for heart health.

Use extra virgin olive oil in salads or to add to cooked foods, but not for high temperature cooking (>350°F)

Unrefined coconut oil is beneficial for mid-temperature cooking (<350°F) with added benefits of medium chain triglycerides, but not for high temperature cooking.

Use avocado oil or light olive oil for high temperature cooking (>375°F). These both have high smoke points compared to other oils. High temperature oils are ideal for searing meats and frying in a wok.

If using canola oil, make sure you buy unrefined. 80% of Canola in US is GMO.

Katie Woeckener RD, CDE, is a registered dietitian and certified diabetes educator at the St. Joseph Health Center for Health Promotion. If you’re in Southern California and want to meet with a registered dietitian or learn more about classes, contact the Center for Health Promotion in Brea at (714) 618-9500 or Santa Ana at (714) 628-3242.

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This information is not intended as a substitute for professional medical care. Always follow your health care professional's instructions.

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