Cooking oils: What's healthy and what's not

With so many types of cooking oil, a trip to the grocery store can feel overwhelming. What kind should you buy? How do you know what's healthy?

Here's a good rule of thumb about fats: Stick with those that are liquid at room temperature. Olive oil, for example, is full of healthy monounsaturated fat and vitamin E. Healthy fats like these can lower cholesterol.

Butter and coconut oil, which stay solid on the counter, are high in unhealthy saturated fats.

But there are some exceptions to this rule. Steer clear of liquid oils made from tropical plants, like liquid coconut oil and palm oil. They're higher in saturated fats than other oils.

You'll also need to pay attention to an oil's smoke point. Oils become unhealthy when they reach too high a temperature.

Mayo Clinic offers these guidelines for buying the right cooking oil for your kitchen:

Healthiest all-around oil

Avocado oil is a perfect kitchen staple. It's full of healthy fat and has a tolerance for heat.

Most overrated oil

Despite its reputation as a health food, coconut oil is nearly 100% fat, most of which is unhealthy saturated fat. Stick with olive oil instead.

Best for stir-fry

Refined sesame oil has a rich, nutty flavor that works well in Asian-style stir-fries.

Best for browning, roasting and searing

Avocado and peanut oils can take the heat of the oven, up to 450 degrees F.

Best for baking and sauteing

Canola, grapeseed and olive oils have a medium smoke point of 350-400 degrees F.

Best for low-heat baking, dressings and marinades

Walnut oil can become bitter if overheated, so it's best when it's uncooked or heated below 350 degrees F. Olive oil works well as a dressing or dip.