Olive

It's long been linked with a lower risk of heart disease and cancer. Olive oil's a key ingredient of the Mediterranean diet, which research shows increases life expectancy.

But olive oil can do so much more. A recent Spanish study published in the journal PLoS One found that a diet rich in mono- and polyunsaturated fats (including olive oil) may ward off depression. Saudi Arabian researchers have discovered olive oil protects the liver against oxidative stress. While in a study published in the Journal of Women's Health, researchers found olive oil helped 80 percent of breast cancer survivors lose weight — helping prevent recurrence of the deadly disease. Phew.

Use it! Choose unrefined, extra-virgin olive oil but don't overcook. Olive oil has a low smoke point — the temperature at which it starts to burn and breaks down. The best way to avoid this is to add olive oil towards the end of cooking.

Bonus tip: Combine olive oil, lemon juice, balsamic vinegar and tahini (sesame seed) paste for a creamy and zesty salad dressing

Canola

Canola oil divides experts, but it has two advantages over olive: canola oil contains some omega-3, while olive oil has none; and it has a higher smoke point. "Canola oil is a good all-rounder, as it's high in monounsaturated fats."

Regardless, canola oil gets a bad rap. Why? According to the US-based Mayo Clinic there's a common misperception that canola oil is made from the rapeseed plant, which contains erucic acid, high levels of which are toxic to humans. While the canola plant was developed through crossbreeding with the rapeseed plant, canola oil contains less than 2 percent of erucic acid. Nothing to worry about.

Use it! Canola oil's high smoke point and tolerance to heat means it is best suited to stir-frying. The subtle taste won't interfere with punchy Asian flavours.

Bonus tip: "Look for certified organic canola oil, so you know it's not genetically modified.”

Rice bran

Rice bran oil is polyunsaturated and free of trans fats. "It also contains vitamins and antioxidants, and is reported to help lower cholesterol and to boost the immune system."  Rice brain oil can lower cholesterol levels in humans. Score!

Use it! Thanks to its delicate flavour and high smoke point, rice bran oil is more versatile than a Swiss army knife.

Bonus tip: If you must deep-fry, opt for rice bran oil over the others. More and more restaurants are making the switch.

Coconut

While the Heart Foundation currently recommends avoiding it (palm oil, too), it may pose some benefits when enjoyed in moderation.
Coconut oil is 92 percent saturated fat, but not all saturated fats are created equal..

The saturated fat in coconut oil is mostly lauric acid, also found in breast milk. It's a proven antiviral, antibacterial and antifungal agent; easily digested and absorbed.
Saturated fats have people scared, but studies show coconut oil can speed up metabolism; it may be good for hypothyroidism [an underactive thyroid].

Use it! Employ this "sometimes food" in Thai cooking. Coconut oil has a high smoke point, around 200°C. Look for cold-pressed or extra-virgin coconut oil, in health food stores.

Bonus tip: Try naturally sweet coconut oil in baking. But it doesn't impart a coconut flavour unless you add desiccated coconut to the recipe.

Flaxseed

Flaxseed oil boasts the highest level of the omega-3 alpha-linolenic acid (ALA) of any vegetable oil. But unfortunately it's not useful as the long-chain omega-3s, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are found in meat sources.

ALA, a short-chain omega-3, must be converted by the body into these long-chain omega-3s. The Omega-3 Centre, the Australian authority on omega-3s, doesn't place much value on ALAs.
The best way to get omega-3s is through fish, meat and eggs.

Flaxseed oil is rumoured to alleviate menopausal symptoms, ADHD and even dry eye syndrome (and more!), but the Mayo Clinic grades all flaxseed oil's health claims under C: "unclear scientific evidence for this use".

Flaxseed may help ovarian cancer patients, however. A five-year University of Illinois study of chickens — who develop the cancer in a similar way to humans — found that a diet enriched with flaxseed decreases the severity of ovarian cancer in hens and ups their chance of survival.

Use it! It might not save your life, but flaxseed oil certainly won't hurt you. It's delicious. "Flaxseed oil goes rancid easily, so keep it in the fridge for up to six weeks; don't expose it to light or heat. It's awesome drizzled over salad.

Bonus tip: "Flaxseed oil is extracted from linseeds, which is always better consumed whole anyway. They're often baked into grainy bread.

The skinny on fat

Veggie oils are good for you, but don't go nuts. Whichever oil you stock your pantry with, remember, it's 100 percent fat. "There is 100g of fat in every 100 millilitres of oil (And 37 kilojoules per gram of fat.).  There's no [recommended daily intake] of oils … but one to two tablespoons per day, or three to five tablespoons for a very active person is recommended