Cooking oil is a staple in most kitchens, for chefs and home cooks alike. In addition to providing us with fats, an essential nutrient, oils can help prevent sticking, sear meat or vegetables to perfection, dress a salad and so much more.
There are plenty of different types of cooking oil from various sources. At the grocery store, you'll find a wide selection of oils from plants, seeds, nuts and fruits. It may leave you wondering: which type of cooking oil is the healthiest? Are the oils in bulk-size plastic gallon containers as good as the ones in fancy little glass bottles?
Where cooking oil comes from and how it's processed can impact the nutrition content, flavor and the temperatures it can withstand. In short, not all oil is equal. We spoke to dietitians about how to choose the right oil for your cooking needs, which oils are healthiest and which oils to limit or avoid.
Is cooking with oil healthy?
"Cooking oil can definitely be part of a healthy diet," says Natalie Rizzo, registered dietitian and nutrition editor for TODAY.com.
Oils are basically pure fat, but fats are an essential macronutrient that plays many roles in the body, from providing us with energy to supporting cell function, TODAY.com previously reported.
Cooking oils provide the body with additional essential fatty acids and other nutrients that promote overall health — not to mention, they make cooking easier and food taste a lot better.
The key is to consume more “good” or healthy fats (polyunsaturated and monounsaturated fats) and fewer “bad” or unhealthy fats (saturated and trans fats), per the American Heart Association.
The Dietary Guidelines for Americans recommends adults limit saturated fat intake to less than 10% of their daily calories.
It's important to note that consuming any kind of fat, good or bad, means additional calories, Beth Czerwony, registered dietitian with the Cleveland Clinic's Center for Human Nutrition, tells TODAY.com. “That needs to be considered when evaluating your diet overall,” Czerwony adds.
Moderation is also key. "The serving size for oil is small — one tablespoon — and having more than that can drastically increase your calorie and fat intake above the recommended amount," says Rizzo. All fat provides 9 calories per gram.
The World Health Organization recommends adults limit their total fat intake to 30% of their daily calories or less. If you're unsure about your caloric needs or how many grams of fat you should be eating per day, talk to a nutritionist or your healthcare provider.
Choosing healthier oils
When selecting a cooking oil, it's important to read the nutrition labels and consider several factors. These range from health benefits to flavor and cooking temperatures.
Saturated fat
The lower the saturated fat content, the better, experts say. “The American Heart Association recommends choosing oils with less than four grams of saturated fats per one tablespoon (or serving),” says Czerwony.
Cooking oils that are high in saturated fats may have negative health effects if used in excess, says Czerwony. Saturated fat can raise “bad” cholesterol or LDL, which can clog the arteries, and consuming high amounts of saturated fat over time increases the risk of heart disease and stroke, per the AHA.
Fortunately, most cooking oils also contain unsaturated fats, Rizzo adds. Oils rich in monounsaturated and polyunsaturated fats provide the body with essential nutrients including vitamins and antioxidants.
Healthy fats can help boost HDL, or good cholesterol, lower LDL, and stabilize blood glucose levels, TODAY.com previously reported. Unsaturated fats are also beneficial for heart and brain health, says Rizzo.
Oils high in unsaturated fats tend to be liquid at room temperature, whereas those high in saturated fats are solid. “A good way to know if it’s saturated fat is to remember, solid at room temperature equals solid in your arteries,” says Czerwony.
Nontropical plant source
Where the oil comes from can also affect the nutrition. "There are oils from fruits, such as olive oil and avocado oil. There are also oils that come from seeds, like canola oil, sunflower seed oil and grapeseed oil. Lastly, there are nut oils, like walnut or peanut oil," says Rizzo.
The experts recommend opting for cooking oils from nontropical fruits, vegetables, nuts or seeds, as these tend to be healthier choices.
Oils from tropical plants — primarily coconut, palm and palm kernel oil — are much higher in saturated fat and remain solid at room temperature, says Czerwony.
Other types of solid fats used in cooking include animal fats — such as butter, lard or tallow — which contain large amounts of saturated fat and have been shown to raise bad cholesterol, per the AHA.
Trans fats are formed through a process which uses hydrogen to turn liquid vegetable oil into a solid fat, such as margarine and shortening, per the National Institutes of Health. These should be avoided due to the health risks.
Refined vs. unrefined
Processing also affects the nutrition content of cooking oils. After being extracted, many plant oils are refined to remove particles and make them more heat- and shelf-stable, Czerwony notes.
Refined oils are often cheaper and last longer. They typically have a very neutral flavor and are very versatile, which makes them a practical option for many home cooks.
However, the refining process also removes a number of nutrients and benefits from the oil, the experts note. “Look for unrefined oils if possible, which will still have more nutrients and antioxidants that are often lost in the refining process," says Czerwony.
Unrefined oils may appear cloudy or contain sediment, but often have a more robust and complex flavor. They also tend to be more expensive and have a shorter shelf life, says Czerwony, but the added health and gastronomic benefits are often worth it.
Bottom line: When choosing between cooking oils at the grocery store, the experts recommend choosing oils that are:
Low in saturated fat (fewer than four grams per tablespoon)
Nontropical
Unrefined
Which oil is best for heating?
Another factor to consider is how you plan to use the cooking oil and the "smoke point," says Czerwony.
All oils have a smoke point, or a temperature at which the oil starts to degrade and burn, which is usually between 325 degrees to 450 degrees Fahrenheit, per the U.S. Department of Agriculture.
“Heating oil breaks down the composition of the oil, which can change the flavor and nutrition,” says Rizzo. Oil can oxidize when it’s exposed to too much heat (or light). “The antioxidants and fat levels in the oil determine how quickly it will oxidize," Rizzo adds.
Heating oil beyond its smoke point can destroy nutrients and produce free radicals, which can damage cells, Czerwony explains. It also causes the oil to taste rancid and can ruin your meal.
Some cooking oils are better to use when cooking with high heat — such as searing or frying. These can withstand higher temperatures without smoking or burning, says Czerwony. Oils with a high smoke point include avocado, canola, peanut and soybean oils.
Other oils are best for cooking with medium heat, such as baking or sautéing. These include olive, grapeseed and vegetable oils.
Cooking oils with a very low smoke point should not be heated. “These are (best) for salad dressings or as a flavor enhancement to finish a dish,” says Czerwony. These include walnut, flaxseed, wheat germ oils and pumpkin seed oil.
Always make sure to read the label on oils, which often indicates the smoke point or the intended purposes and cooking methods.
What is the healthiest cooking oil?
Olive oil
Olive oil is the top pick among the experts due to its variety of well-researched health benefits. It's also versatile and can be used to cook or enhance many hot and cold dishes.
Olive oil is packed with healthy fats, including monounsaturated fatty acids — it has the highest amount of any plant oil, per the AHA — which can help lower LDL and blood pressure.
It's also rich in plant-compounds called polyphenols, vitamins and antioxidants, which have been shown to decrease inflammation and improve heart health, says Czerwony. “Including olive oil in the diet has been linked to reductions in heart disease, diabetes and other chronic diseases," Rizzo adds.
The experts recommend opting for “extra virgin olive oil” or EVOO, as this is the least processed and typically cold-pressed which retains more nutrients and flavor.
It can withstand temperatures up to 410 degrees Fahrenheit, per the USDA, which makes it a great option to bake, sauté, roast and more. Extra virgin olive oil also has the lowest oxidation rate of any oil, per the Cleveland Clinic, which means it's more stable and less prone to emitting free radicals when heating.
One tablespoon or serving of olive oil contains about 119 calories and 13.5 grams of fat, according to the USDA.
Other healthy cooking oils
There are a number of other nontropical plant and vegetable oils which provide good fats, vitamins and antioxidants, making them a healthy choice in the kitchen. When choosing an oil, it’s important to consider the flavor and smoke point, as well as any food allergies.
Avocado
Canola
Corn
Peanut
Safflower
Soybean
Grapeseed
Sunflower
"Vegetable oil" is typically made from one or a blend of these oils. These cooking oils can all be part of a healthy diet when consumed in moderation.
What is the least healthy cooking oil?
The least healthy cooking oil is coconut oil due to its high saturated fat content, the experts note. “Basically every single oil, except for coconut oil, is a good source of unsaturated fats and is a healthy option for cooking,” says Rizzo.
Coconut oil is 80-90% saturated fat, says Rizzo, compared to other oils which are typically 10–20% saturated fat. “The AHA discourages using coconut oil since the saturated fat can raise LDL cholesterol,” says Rizzo.
“Coconut oil has not had any large-scale research to support any health benefits and it far exceeds four grams saturated fats per tablespoon, making it higher in fat than butter," says Czerwony.
If you can't avoid coconut oil, try to limit your intake and only use small amounts for cooking, says Rizzo. Palm and palm kernel oils are also high in saturated fats and should be avoided when possible, says Czerwony.
Tips for using storing and cooking with oil
Common habits and mistakes in the kitchen can compromise cooking oil's freshness, nutrition, and taste. It’s important to store and use cooking oil properly, says Czerwony.
Choose oil in dark, opaque bottles which protect it from light
Store oil in a dark, cool place to avoid oxidation or overheating
Use cooking oil within several months of opening
Do not use expired cooking oil
Discard oil that smells rancid
Do not use oil after it smokes or catches fire
Do not reuse cooking oil
Do not refrigerate cooking oils
This article was originally published on TODAY.com
