Veggies are extremely versatile, so the method that you use to cook them can make a big difference to the amount of nutrients you receive when you eat them. Each type of vegetable has a unique blueprint of nutrients and phytochemicals, all of which play essential roles in keeping your body healthy.
Some veggies are best eaten raw, or cooked in a way that minimises the loss of water-soluble vitamins — such as vitamin C and the B-group vitamins, which can be destroyed by heat.
Other vegetables like potatoes need to be well cooked to get the maximum benefit from specific phytonutrients. Follow our guide to get the most nutrition out of your veg.
Our pick: Steaming
Brassicas, such as cauliflower, cabbage, broccoli and broccolini, Brassicas high in vitamin C, folate, iron, calcium, selenium, fibre and antioxidants. They pack their biggest nutritional punch via steaming, which lets them keep more of their vitamin C and iron benefits.
Steam for as little time as possible — the veggies should still be brightly coloured and have an audible crunch. Stir-frying is another great option for brassicas, but make sure you cook using a spray oil, because using water to stir-fry increases nutrient loss.
Our picks: Microwave or steaming
Potatoes and sweet potatoes (kumara) are popular veg due to their adaptability and delicious flavour — but any method of cooking that involves lots of oil and salt isn’t going to yield the best nutritional benefits.
Similarly, you can lose water-soluble vitamins through boiling potatoes, so steaming is the best way to go. Wash the potatoes and pierce them a few times with a fork before cooking. If you’re microwave- steaming, wrap the spuds in a damp paper towel after piercing and cook for several minutes, or until they’re soft.
Our pick: Stir-frying
Leafy greens such as spinach, silverbeet and watercress are great sources of vitamins A, C, E, folate, calcium and iron. By not using heat, you’ll maximise their nutritional value, so they’re great salad material. To get the most from leafy greens, quickly stir-fry them or stir through a hot dish. The leaves should stay dark green, and only just begin to wilt. Avoid cooking leafy greens in water, as many of the water-soluble vitamins are washed away with the green water.
Our pick: Roasting
Although technically a fruit, tomatoes are often viewed and used as a vegetable. They’re rich in healthy lycopene, carotenoids, vitamin C and fibre. To increase the ‘bioavailability’ of both lycopene and carotenoids, lightly sauté or roast tomatoes in a little oil. The skins will wrinkle, the colour will deepen and the sweetness will intensify. Use them as a side dish to accompany meat dishes, or turn them into sauces or pastes.
Raw tomato is of course a popular and nutritious addition to most salads. It’s a good source of vitamin C when raw, but not such a nutritional powerhouse as when it is cooked.
Our pick: Grilling
Bright and beautifully coloured, capsicum is rich in carotenoids, vitamin C and fibre. To maximise these healthy nutrients, slice capsicums into large pieces to reduce the vitamin loss while they are cooking, then stir-fry for less than 3 minutes in a teaspoon of oil. The skin should remain bright, firmly attached and slightly crunchy. Alternatively, grill some capsicum halves for a few minutes, peel off the skin and dress the flesh with olive oil and balsamic vinegar.
Raw capsicum is packed with readily available vitamin C — so add it to salads or sandwiches, or dip it in hummus.
Our pick: Stir-frying
Zucchini’s key nutrients are folate (important for pregnant women), beta carotene (to help boost your immune system), and fibre (good for your gut). Steaming preserves the most nutrition, so steam briefly to retain zucchini’s firmness and the bright green skin. Stop steaming as soon as the centre flesh turns semi-transparent and seeds are more visible.
You can also retain zucchini’s nutrients by stir-frying it quickly after a spray of oil, or grating it into other dishes. Make savoury pancakes by grating a small zucchini into the batter. You can also shred or grate raw zucchini to use in salads or sandwiches
Cooking methods at a glance
A great way to cook! Steaming minimises the loss of nutrients from vegetables. You can choose two methods: a steamer placed over boiling water, or a microwave (see below).
HFG tip: Don’t cook vegetables too long. Perfect steamed veggies are brightly coloured and tender-crisp, rather than mushy.
One of the fastest ways to cook and steam veg. When steaming, microwaving is the best method to use, because you lose slightly less nutrient as a result of the quick cooking time.
HFG tip: Place veggies in a microwave-safe dish and steam them with a small amount of water for just a few minutes.
Chargrilling and BBQ
These popular cooking methods can enrich the flavour of eggplant and capsicum — but try to avoid charring food, as the black burnt bits are carcinogenic.
HFG tip: When you are barbecuing or chargrilling, lightly spray the food, not the barbecue plate or chargrill pan, with oil. This prevents the barbie from smoking and food from sticking.
This simple cooking method is another healthy way to get the most out of veg like starchy tubers or coloured root vegetables — just watch the oil!
HFG tip: To make homemade chips: thinly slice potatoes, sweet potatoes or carrots. Place on a baking tray lined with baking paper. Spray with a little oil, then roast until golden.
Stir-frying’s fast cooking time means more nutrients are retained. Just spray a hot wok or frying pan with oil and add veggies such as carrot and capsicum.
HFG tip: A bag of frozen ‘stir-fry mix’ veggies is a great stand-by for those nights when you’re short on time.
For more on this topic read: Raw or cooked food: Which is healthier?