Guide

An air fryer is a small convection oven with a fan and a basket. That's the whole technology, and it's worth saying plainly, because a lot of claims get attached to it.

What it changes: the fat, the cooking time, and whether vegetables get eaten. What it doesn't change: the carbohydrate in whatever you put in the basket.

The honest starting point

A potato cooked in an air fryer contains the same carbohydrate as a potato cooked any other way. Air frying is not a glycemic intervention. If chips are a problem for your numbers, chips made with less oil are still that problem.

What does change is the fat and calorie load. Deep frying adds substantial oil; air frying uses a spoon of it or none. For someone managing weight alongside blood sugar, that's a real difference over months, just not one that shows up on a meter within two hours.

Where it does move the glycemic needle

Two effects are worth knowing about.

The first is what the machine displaces. Air fryers get used for vegetables at a rate ovens never achieved, because six minutes is a different proposition from preheating an oven for forty. Roasted cauliflower, broccoli, green beans, peppers, and courgette all come out well, and every one of those replacing a starch on the plate does more for glycemic load than any cooking method could.

The second is texture substitution. Crisp is usually what people want when they reach for chips, and crisp is achievable from things that aren't potato. Roasted chickpeas, celeriac batons, courgette rounds, and halloumi all deliver it. Chickpeas in particular go from a GL around 3 per half cup to a crunchy snack at the same number.

What about the cooking-and-cooling effect

Cooling cooked starch converts some of it to resistant starch, and that applies here as it does anywhere. Air-fried potatoes cooled and reheated the next day carry a lower glycemic load than the same potatoes fresh from the basket.

Reheating in the air fryer is where the machine genuinely outperforms a microwave, because it restores texture instead of steaming it away. Cook a tray of potatoes on Sunday, chill them, and crisp them in six minutes during the week. Lower load, better result, less effort.

The acrylamide question

High-temperature cooking of starchy foods produces acrylamide, a compound formed when sugars and the amino acid asparagine react above about 120°C. It's classified as a probable human carcinogen based on animal studies, and it forms in air fryers as it does in ovens and deep fryers.

The exposure from home cooking is small, and the practical guidance is straightforward: cook to golden rather than dark brown, don't store potatoes in the fridge before frying (cold storage raises their sugar content, which increases acrylamide formation), and soak cut potatoes for half an hour before cooking if you want to reduce it further.

I mention it because air fryers get used at high temperatures on starchy food more often than ovens do, not because it's a reason to avoid the machine.

What works especially well

• Chickpeas: drained, dried, tossed with oil and spice, 15 minutes at 200°C. The best low-GL crunchy snack there is.
• Salmon and white fish: 8–10 minutes, no carbohydrate, hard to overcook.
• Chicken thighs: skin crisps properly, which is the thing ovens do slowly.
• Tofu: pressed and cubed, it comes out genuinely crisp without a deep-fry.
• Halloumi and paneer: zero carbohydrate, and they turn a salad into dinner.
• Frozen vegetables: straight from the freezer, no thawing, better texture than boiling.

What it isn't good for

Anything with a wet batter, which drips through the basket. Large joints of meat, which need a real oven. Leafy greens, which fly around in the fan and burn.

And the pre-packaged frozen products that dominate air fryer marketing — the breaded, coated, seasoned items — are still high-GL processed food cooked slightly more efficiently. A breaded chicken product carries the same coating whether the fat came from a fryer or a spray bottle.

Capacity is the real constraint

The basket is small, and that shapes what the machine is good for more than any nutritional consideration does.

Food needs space around it to crisp. Overfill the basket and you get steamed food with a dry surface, which is the outcome that makes people conclude air fryers are overrated. For one or two people it's the right size appliance; for four it usually means cooking in rounds, and the second round is where the enthusiasm dies.

The workaround that holds up is using it for the component that benefits — the protein, or the vegetable that needs crisping — while the oven or hob handles the bulk. Trying to cook a whole family dinner in a two-litre basket is how a useful tool ends up in a cupboard.

The practical summary

Treat the air fryer as a tool for eating more vegetables and more protein, not as a way to make starch acceptable. The people who get the most from it are the ones who use it to roast things they'd otherwise have boiled or skipped.

If it's already in the cupboard and it currently makes chips twice a week, the highest-value change is a single tray of vegetables alongside dinner three times a week. That's a glycemic load improvement the machine actually delivers.

And if you're buying one, buy it for the protein and vegetable work rather than for the chips. The chips are the demo that sells the appliance. The tray of roasted broccoli at 7 p.m. on a Tuesday is the thing that changes a week of eating.