Deep-fried foods play a role in many traditional cuisines and are a staple of the fast food industry.
However, deep-fried foods can have a negative effect on health.
This will depend partly on how often you eat it, but also on the type of oil you use and how you use it.
This article reviews the healthiest oils for frying.
In this article
How does deep frying work?
Deep frying involves cooking food by submerging it in hot oil.
The ideal temperature is around 350–375°F (176–190°C).
Submerging food in oil at this temperature causes its surface to cook almost instantly. As it cooks, it forms a seal that the oil cannot penetrate.
At the same time, the moisture inside the food turns into steam, cooking the food from the inside. The steam also helps keep the oil out of the food.
However, you have to have the right temperature:
- If the temperature is too low, the oil will seep into the food, making it greasy.
- If the temperature is too high, it can dry out the food and oxidize the oil.
Summary: Deep frying involves submerging food in hot oil. At the right temperature, this will instantly cook the surface and trap moisture inside the food.
Stability of cooking oils is key
Some oils can withstand higher temperatures than others.
- A healthy oil for cooking will have a high smoke point.
- A healthy oil for cooking will be stable, so they don’t react with oxygen when heated.
Oils with higher levels of saturated fats tend to be more stable when heated.
Oils that are mostly saturated and monounsaturated are good for frying.
However, cooking oils that contain large amounts of polyunsaturated fats are less suitable for frying.
This is because polyunsaturated fats contain two or more double bonds in their chemical structure. When exposed to high heat, these double bonds can react with oxygen and form harmful compounds.
Taste is also important. When deep frying, oils with a neutral flavor are usually preferable.
Summary: Oils that consist mostly of saturated and monounsaturated fats are best for deep frying because they’re the most stable at high heat.
Coconut oil is a healthy choice for deep frying
Coconut oil may be a good choice.
Studies have shown that its quality remains acceptable even after 8 hours of continuous deep frying at 365°F (180°C).
Over 90% of the fatty acids in coconut oil are saturated, making it heat-resistant.
Experts disagree on the benefits and drawbacks of using saturated fats.
Mainstream organizations, such as the American Heart Association, recommend limiting the intake of saturated fats to 5–6% of total calories. However, various studies have concluded that saturated fats may not increase the risk of heart disease.
When choosing coconut oil, remember that some varieties can leave a flavor or smell that not everyone enjoys. It’s best to try a few brands until you find one suitable.
Summary: Coconut oil is high in saturated fats, which means it’s stable and doesn’t appear to change quality during deep frying. This may make coconut oil a good choice for frying.
Lard, tallow, ghee, and drippings
Animal fats, such as lard, tallow, ghee, and fat drippings, can be excellent choices for deep frying.
Benefits include:
- the flavor and crispness they add to food
- their ability to resist damage when fried
Most fatty acids in animal fats are saturated and monounsaturated. This makes them resistant to high heat.
However, the fatty acid content can vary, depending on the animal’s diet.
Grain-fed animals may have more polyunsaturated fatty acids in their fat stores than pasture-raised or grass-fed animals.
Suggested read: Sunflower oil: Nutrition, benefits, downsides, and more
The best choice, therefore, comes from animals that have been allowed to roam and eat naturally.
You can buy ready-made lard or tallow from the store, or save the drippings from meat to use later.
Butter is unsuitable for deep frying. It contains small amounts of carbs and protein that burn when heated. Clarified butter and ghee are better options.
Summary: Animal fats consist mainly of saturated and monounsaturated fats, making them suitable for cooking at high temperatures.
Other good choices for deep frying
There are several other good options.
Olive oil
Olive oil is one of the healthiest fats.
It’s resistant to heat because, like animal fats, it’s high in monounsaturated fatty acids. These have only one double bond, making them relatively stable.
In one study, researchers used olive oil in a deep fryer for over 24 hours before it oxidized excessively.
In theory, this makes it a great choice for deep frying.
However, the flavor and fragrance of olive oil may deteriorate when heated for a long time.
Avocado oil
Avocado oil has a similar composition to olive oil. It’s mainly monounsaturated with some saturated and polyunsaturated fats mixed in.
Refined avocado oil has a high smoke point of 520°F (270°C) and a slightly nutty taste.
Peanut oil
Peanut oil, or groundnut oil, has a high smoke point of about 446°F (230°C).
It’s popular for deep frying because it has a neutral taste.
However, it may not be as healthy as some other choices.
It contains around 32% polyunsaturated fats. This relatively high amount makes it vulnerable to oxidative damage at high temperatures.
Palm oil
Palm oil consists mostly of saturated and monounsaturated fats, making it a great choice for deep frying.
The flavor can be neutral, particularly if you use the unrefined variety known as red palm oil.
Suggested read: Is olive oil a good cooking oil?
However, some people have concerns about the sustainability of cultivating and harvesting palm oil.
Summary: Olive oil and avocado oil are good choices for deep frying. Peanut and palm oils are less suitable for health or environmental reasons.
Options that are unsuitable for deep frying
Some fats and oils aren’t suitable for deep frying.
They include vegetable oils that are high in polyunsaturated fatty acids, such as:
- soybean oil
- corn oil
- canola oil (also called rapeseed oil)
- cottonseed oil
- safflower oil
- rice bran oil
- grapeseed oil
- sunflower oil
- sesame oil
These oils for deep frying can produce large amounts of oxidized fatty acids and harmful compounds.
Summary: Vegetable oils high in polyunsaturated fatty acids are unsuitable for deep frying. They are less heat-resistant than oils or fats high in saturated or monounsaturated fatty acids.
Deep frying adds calories
Even if you use a healthy oil, deep frying will add a lot of calories to food, so it’s best not to eat it too often.
The extra calories typically come from coatings, including batter and flour, plus the oil that sticks to the food after cooking.
For example:
- Deep-fried chicken wing: 159 calories and 11 grams of fat.
- Roasted chicken wing: 99 calories and 7 grams of fat.
High consumption of deep-fried foods is linked to weight gain, especially in people with a family history of obesity.
To minimize the extra calories, cook the food at the right temperature and no longer than necessary.
Summary
Deep-fried food doesn’t have a reputation for being healthy. Eating too much of it cooked in the wrong oils can lead to health problems.
However, deep frying with the right oils can make a tasty treat in moderation.
You can find more information about which oils to use in cooking here:
