The best (and worst) cooking methods for preserving the nutrients in your food

Nowadays, it seems like we’re all trying to cook healthier, more nutritious meals. However, figuring out what makes a meal truly healthy isn’t always clear or straightforward. There is a lot of conflicting advice, with restrictive diet trends and other misinformation floating around the internet.

While there is a lot of noise to cut through, better preserving the nutrient content of your food is a surefire way to get more out of your meals. However, when it comes to nutrient retention, not all cooking methods are created equal. Should you roast everything in your oven, give it all a quick stir-fry, steam or slow cook in a multi cooker or go all in on air frying?

To find out more about how cooking affects the nutrients in your food, as well as which methods we rate as the best (and worst) for preserving nutrients, keep reading below.

How does cooking food affect its nutrient content?

Before we look at specific methods and appliances, let’s get a brief overview of how cooking food affects its nutritional content. Generally speaking, all cooking methods and food preparation involves some level of nutrient loss. Some nutrients stored in a vegetables’ skin will be lost during peeling, heat-sensitive vitamins, such as Vitamin C and some B Vitamins, can be destroyed at certain temperature thresholds, while water-soluble and fat-soluble vitamins can migrate to the water or oil used during cooking and subsequently be left behind. As a rule of thumb, the less time, heat and water your cooking method involves, the less nutrient loss will occur.

On the other hand, aside from improving the taste and making it safer to heat, cooking food also has many nutritional benefits. Certain carbohydrates, proteins and lipids become easier to digest and absorb when cooked, while some antioxidants, like carotenoids, only become bioavailable when heated.

Vitamins A, K, D and E can also have their absorption improved by combination with fat during cooking. While eating some raw fruits and vegetables can give your diet a nutritional boost, it’s arguable that most foods benefit from cooking in terms of enjoyment, safety and nutritional value.

The best (and worst) cooking methods for preserving nutrients

Now that we have a general understanding of how nutrients are affected by cooking, let’s take a look at some specific processes:

Steaming

Steaming is widely regarded as one the healthiest cooking methods and one of the best options for nutrient retention. Steaming is a gentle, speedy and relatively low-heat cooking method that introduces very little water and no fat to your food. Vegetables such as broccoli and spinach are perfect candidates for steaming. Where these vitamin-rich veggies would usually lose up to 50% of their Vitamin C when cooked via other methods, steam-cooked spinach and broccoli have been found to lose as little as 10% of their vitamin content. While you can steam vegetables at home in a pan or in your microwave, for the best results and simplest set-up we recommend using a dedicated multi cooker with a Steam setting.

READ NEXT: Best microwaves

Microwaving

The humble microwave gets a lot of bad press, with most people associating it with unhealthy microwave meals and other quick fixes. In terms of nutrient preservation, however, microwaves are actually pretty hard to beat. As noted above, the longer your food is exposed to heat and the higher levels of heat, the more damage is done to its nutrients. Microwaves typically operate at lower temperatures than ovens, are one of the quickest cooking methods and rarely involve additional oil or water. All of this means that relatively little nutrient content is shed during cooking.

Roasting / Baking / Air frying

The main loss of nutrients that occurs when roasting is the destruction of heat-sensitive B vitamins and some Vitamin C. To minimise the loss of nutrient content, you can try lowering temperatures to below 200°C and keeping cook times as short as possible where you can.

What technically differentiates baking from roasting is the difference in items you bake and roast, as well as the different temperatures used. Roasting tends to take place at 200°C and above, while oven cooking that occurs at 190°C and below can generally be termed as bakes. Baking is less aggressive and helps to retain more moisture in delicate foods. So, if you want to maximise the nutrient content in your meals, baked vegetables could be the way to go.

The third method in the convection cooking trifecta is air frying. Air fryers are a great way to cook up crispy vegetables and more, while still retaining a lot of the nutrient content of your favourite foods. This is because air fryers have powerful fans that distribute heat quickly and, and evenly, making for some of the speediest cooking times outside of microwaves. This efficient set-up allows for fast, lower-temperature cooking that requires little to no oil, three factors which ensure lower levels of nutrient loss.

READ NEXT: Best slow cookers

Stewing / Slow Cooking

As a rule of thumb, the best cooking methods for nutrient preservation are quick and eschew the addition of water. An exception to this rule is when the cooking water is consumed as part of the dish itself – think stews, soups and curries. When cooking a one-pot dish like this, you might lose some water-soluble vitamins and minerals from the vegetables themselves, but you’ll still reap most of the benefits by consuming the nutrient-rich broth you’ll be creating.

An especially good way to preserve nutrients when making these types of meals is to use a slow cooker. This lengthy but gentle, low temperature method can minimise the amount of nutrients destroyed by heat and will help retain them in the broth as it won’t be boiled or drained away. While you can get dedicated slow cookers, nearly every contemporary multi cooker will have a Slow Cook setting, as well as a wide range of other useful features such as steaming, air fryer and more.

Pan-frying / Stir-frying

In terms of nutrient retention, pan-frying isn’t the best option. It’s typically a high-heat affair that requires a lot of oil, both of which can cause nutrients to degrade or leach from your food. If you’re dedicated to the sear and sizzle of a hot pan, stir-frying is a better alternative to pan-frying, as its fast cooking times means you’ll retain more key vitamins and minerals when cooking.

READ NEXT: Best kitchen taps

Boiling

Although boiling can be considered a healthier cooking method due to the lack of oil, it’s actually one of the worst methods when it comes to nutrient preservation. Boiling vegetables causes much of the water-soluble vitamin content to be lost to the water you’re cooking in. In comparison to steaming, boiling spinach and broccoli can lead to them losing up to 50% of their vitamin C content. So while boiling is a lower calorie solution to cooking vegetables, it doesn’t mean it’s the healthiest. If you’re also serving your dinner with gravy, then you can preserve some of the lost nutrients by using the vegetable water as the base for your gravy granules, not dissimilar to the slow cooking/stewing process mentioned above.