Air fryers are the third most used kitchen appliance, just behind microwaves and toasters. Photo / Getty Images
Air fryers are the third most used kitchen appliance, just behind microwaves and toasters. Photo / Getty Images
Air fryers cook food faster and use less oil, making meals lower in fat and calories.
They are more energy-efficient but have limited capacity, suitable for small portions.
While healthier, air fryers require proper cleaning to avoid harmful oil build-up and trans fats.
Air fryers are all the rage, promising a healthier way to prepare your food. We look at how they really compare to the conventional oven.
Whether you want to cook a quick jacket potato, crispy fries, a roast dinner for the family, or even a batch of fudgy brownies, look no further than the miniature oven on your kitchen worktop. Traditional ovens are old news as this culinary upstart, the air fryer, promises a healthier way to prepare all your favourite foods.
And it’s rare to find a kitchen without one these days. They’re the third most used kitchen appliance (just behind microwaves and toasters) and almost 60% of people in the UK now own one, according to a Good Food Nation study.
Jamie Oliver is a huge fan, and with both a TV series and cookbook dedicated to the appliance, he claims they have “well and truly earned their place in our kitchens”.
But how do they really compare to the conventional oven – and are they as healthy as claimed?
How do air fryers work?
Air fryers are like miniature fan ovens, only they’re much smaller and the fan is much stronger, explains Dell Stanford, a senior dietitian at the British Heart Foundation. A heating element sits at the top of the fryer and the food goes into a perforated drawer at the bottom. When heat is emitted into the main chamber, a powerful fan blows hot air around the food to cook it.
“Because they’re much smaller than a conventional oven, they tend to heat up and cook food much more quickly,” Stanford explains. “They’re more energy efficient and cost-effective.”
Ninja claims its “Foodi Dual Zone” air fryer cooks up to 75% faster than fan ovens, while the Instant Vortex Plus 6-in-1 model uses up to 80% less energy.
“The downside is that because they’re smaller and have less capacity than a conventional oven, you can only really cook food for one or two people. When they’re overfilled, they don’t tend to work as well,” Stanford says.
What are the health benefits of air fryers?
1. You cook with less oil
While food cooked in an air fryer still benefits from a small amount of oil, roughly a teaspoon for a batch of chips or half a tablespoon for four chicken breasts, it is far less than what is required for oven cooking or deep-frying. One study in the Journal of Food Science proved that French fries cooked using an air fryer was substantially lower in fat.
This is because it crisps up food by circulating hot air, rather than immersing it in oil. Air fryer meals are therefore comparatively lower in fat and calories (as one gram of oil is equivalent to around nine calories).
“Whilst 100g of deep-fried chips can contain around 15g of fat, air fried versions may have as little as 3-5g,” explains Rob Hobson, a nutritionist and author of Unprocess Your Family Life. “They’re particularly helpful if you’re watching your weight or cutting back on saturated fat.”
The health risks of excessive oil intake are well established. A diet high in saturated fats has been consistently linked to increased LDL cholesterol levels which can lead to heart problems and cardiovascular diseases.
2. They can reduce reliance on UPFs
Because the food cooks far quicker in an air fryer, it makes it easier to prepare meals from scratch without the time commitment of conventional cooking, Hobson says. “That might help reduce reliance on ultra-processed foods (UPFs), especially ready prepared foods that can be high in saturated fat, salt and a variety of additives,” he explains.
“You could easily make your own version of popular convenience foods at home in no time, things like homemade fish fingers, falafel or veggie nuggets.”
Because less oil is required to make the same food you would cook in an oven or deep-fryer, air fryer meals tend to be lower in calories. Photo / Getty Images
Air fryer recipes have gone viral across the internet, with websites and influencers dedicated to promoting healthy fuss-free meals.
However, air fryers are, of course, only as healthy as the food you put in them, Stanford warns. “I saw a recipe recently for an air fryer cheese toastie, where two slices of white bread were coated in butter, and filled with two different types of cheese. Just because it’s cooked in an air fryer, it doesn’t make it healthy.”
Air fryers may be better at preserving the natural nutrients in food, especially certain vitamins sensitive to heat and oil, Hobson explains.
A 2024 study in the Foods journal found that many vitamins are sensitive to high temperatures, meaning that during frying, they can be lost to the oil. Vitamin E is particularly sensitive to this. In another study in the International Journal of Nutrition and Food Engineering, researchers discovered that salting and frying swordfish in olive oil led to a significant decrease in vitamin B.
As air frying is quicker and uses hot air rather than lots of oil, natural vitamins and nutrients are likely to be better retained, which is beneficial for our health.
4. Lower levels of certain chemicals
Acrylamide is a chemical substance formed when starchy foods, such as potatoes, are cooked at high temperatures. It is a natural byproduct of the cooking process and has always been present in our diet.
However, it’s been classified by the International Agency for Research on Cancer (IARC) as a probable human carcinogen, Hobson explains, and has caused cancer in laboratory animals when consumed in high volumes.
While air fried foods still contain acrylamide, the levels are likely lower than deep frying or roasting in a very hot oven, Hobson says. One study in the Journal of Food Science found that air frying potatoes may reduce acrylamide content by up to 90% compared to conventional deep fat frying.
The Food Standards Agency (FSA) advises aiming for a golden yellow colour or lighter when frying, baking, or roasting starchy foods to reduce acrylamide consumption.
Does air frying pose any health risks?
1. Potential dangers of non-stick linings
Many older air fryers are coated with non-stick materials such as Teflon (PTFE) or bisphenol-A (BPA). The latter has been linked to health issues including respiratory irritation and eye problems.
You’re unlikely to consume large amounts of these chemicals unless the non-stick lining of the air fryer becomes damaged and releases them. This could be the result of a metal utensil scratching the non-stick surface or the air fryer being heated to extreme temperatures.
To avoid this risk, Jenna Hope, a registered nutritionist, says to avoid using a knife or sharp utensil on the air fryer lining. “If you do need to remove food from the lining always use a silicone utensil to prevent scratching,” she says.
When cleaning the air fryer, use a soft sponge and soapy water rather than putting the individual parts in the dishwasher, she adds. You can also mitigate risk by using a non-toxic silicone lining, which can be bought separately and is removable, to prevent food becoming stuck.
Many air fryers are now designed to be BPA-free, with manufacturers opting for stainless steel or high-quality plastics instead.
2. Oil can become rancid and build up unhealthy fats
Just like leaving an oven or deep fat fryer unwashed for a long time, failing to regularly clean your air fryer can result in dangerous oil build-up, explains Hope.
“Oil or natural fats from food can become rancid and build up if you’re not cleaning your air fryer properly,” she says. “The rancidity is only going to ramp up if you continue to cook and not properly clean after.”
This can result in a build-up of trans fats, a type of unsaturated fat which is considered harmful to health. Excessive consumption of trans fats can lead to high cholesterol and heart problems.
“Just make sure you’re always properly cleaning your air fryer after use,” Hope urges.
While speed and convenience are among the air fryer’s biggest benefits, they may also lead to unnecessary snacking and overeating, Hobson explains, especially with foods that are easy to eat in excess such as chips.
He urges people to be mindful and continue to eat in moderation, not using the ease of air frying as an excuse to overeat. “It’s worth keeping an eye on how often you’re reaching for the air fryer and what you’re putting in it,” he says.
Air fryers vs the conventional oven
The main differences with a standard oven is that air fryers are smaller which means the airflow is more restricted and they can cook food faster, Hope explains. Most foods that you cook in an oven you can cook in an air fryer – with their capacity being the main limiting factor.
They require less oil than oven cooking which means the same food can be cooked in a relatively healthier way, with less added calories and fat, Hobson says.
What should you not cook in an air fryer?
“For certain dishes like fatty cuts of meat or slow-cooked meals you will probably get a better flavour and texture from longer, slower cooking methods,” says Hobson.
Slow cooking may also better preserve the nutrients in these foods as they are cooked at a lower temperature for a longer period.
Also consider cooking leafy greens, such as spinach or kale, in your normal way, as the air fryer fan can cause them to fly around and burn. It means they require more oil to ensure they remain in the basket and don’t shrivel anyway, so the potential health benefits of air frying may be lost.
Finally, one study in the Journal of Food Science that assessed the impact of cooking sardines in an air fryer found that their healthy fat content (poly-unsaturated fats) decreased. Meanwhile, cholesterol oxidation products (COPs) slightly increased – these may negatively affect cholesterol levels. Therefore, when you’re next cooking sardines, consider doing so in the oven or on the hob – or, air fry them with fresh herbs like parsley or chives, which appeared to help reduce these damaging effects.
So which is the best way to cook: by air, or our old friend, the conventional oven? “It may be easier to use an oven or hob when cooking for a crowd just for the sake of space and efficiency, whilst air fryers are ideal for small portions or quick meals,” says Hobson, with an added health bonus.
