Cooking oils: How to choose a healthy option

When it comes to cooking oils, there are so many choices these days. It is important to be aware that not all oils are created equal. Understanding the nutritional properties and composition of different oils will help you make the best choice for your dish and your health.

Cooking oils are liquid fat derived from plants, nuts or seeds. All oils have a similar energy content (~3500kJ per 100ml, or about 700kJ per tablespoon), but they can differ significantly in fat types and ratio of fats they contain.

This is how we differentiate what oils are healthier than others. Polyunsaturated and monounsaturated fats are preferred as they are more ‘heart healthy’, due to the fact they can lower total and LDL (‘bad’) cholesterol. Monounsaturated fats also increase HDL (‘good’) cholesterol. Saturated fats increase total and LDL cholesterol.

All oils are energy dense and should always be used sparingly. The recommended daily total intake of fat is around 70g, and 24g or less when it comes to saturated fats. One tablespoon of oil contains approximately 18g total fat (20 % of total daily intake), therefore when cooking aim to only use 1-2 tablespoons of any type of oil.

The smoke point is the temperature at which oil starts to degrade – this affects the quality of the oil and the flavour it produces. The smoke point is affected by the composition of the oil, and how the oil has been processed; therefore it can vary slightly between different brands of the same type of oil. Oils with a low smoke point tend to have a rich flavour and are best used with minimal or no heat (ideal for dressings and dips).

Oils with a high smoke point generally have a more subtle flavour and are well-suited to dishes that require high heat, but can also be used in sauces, dips and dressings. Sunflower and canola oil are some the best choices for sautéing and stir-frying. They contain heart-healthy fats, have a mild flavour and are not expensive.

Other good choices for high-heat cooking include light olive oil, sesame oil and rice bran oil. Use spray oils as much as possible to limit adding extra calories. Olive oil and vegetable oil sprays are well-suited to oven-cooking and barbecuing. When lining baking tins use baking paper rather than oil, or use an oil spray.

Coconut and palm oils are widely used in commercially-baked goods, yet it is recommended to avoid these due to their high saturated fat content. Extra virgin olive oil, flaxseed and walnut oils work well in dressings, sauces and dips. These oils are best used in cold dishes as they can be very unstable and quickly deteriorate when heated.

This can affect flavour, but also the chemical structure changes and these oils (which are normally unsaturated) can actually act like saturated fats in the body.

Common oils

  • Avocado oil comes from avocado pulp, has a high smoke point, and is a source of monounsaturated fat and vitamins A, D and E. It has a mild flavour and can be used to sauté meats and fish, or works well in salad dressings.
  • Rice bran oil is extracted from the germ of rice grains.It’s high in vitamin E, monounsaturated and polyunsaturated fats, but also has a relatively high saturated fat content compared to other plant-based oils. It has a high smoke point and is commonly used in stir-fried dishes.
  • Palm oil is best avoided as it is almost 50% saturated fat. It can sometimes be found in vegetable oil blends.
  • Canola oil comes from the rapeseed plant. It is high in monounsaturated fat and has one of the lowest saturated fat contents of all oils.It contains heart-friendly omega-3s and is suitable for both low and high heat cooking.
  • Light/Extra Light olive oil is milder than extra virgin olive oil. It is derived from the second pressing of the olives. The ‘light’ description refers to the lighter colour and flavour produced; there is no difference between the fat and energy content of extra virgin olive oil. Yet it does have a higher smoke point.
  • Peanut oil is suited to stir-frying. It’s moderately high in monounsaturated fat and does not absorb or transfer flavours during cooking. It is often used in Asian dishes.
  • Sunflower oil is rich in vitamin E and low in saturated fat. It has minimal flavour and can be used in most types of cooking.
  • Sesame oil has a rich, nutty taste and works well in high-heat dishes, as well as cold Asian-style salads.
  • Macadamia oil like peanut oil has a strong, nutty flavour and is suitable for both high-heat cooking and salad dressings. It’s also very high in monounsaturated fats.
  • Extra virgin olive oil comes from the first pressing of the olives and contains mainly monounsaturated fats. It is best used in dressings, marinades, sauces and low-heat cooking (such as roasting), but can also be used for high-heat cooking. It has a strong distinct flavour.
  • Coconut oil is pressed from coconuts, and although contains some medium chain triglycerides, is almost 90 per cent saturated fat. Due to its high saturated fat content it is best avoided.
  • Flaxseed/linseed oil is rich in omega-3s, yet isn’t heat stable has a very low smoke point. It is therefore best used in cold dishes like salads.

As you can see there is not one oil that fits all! It is best to always have a few different oils in the cupboard that are high in healthy unsaturated fats, to help cover different cooking styles. For example always have a good all-rounder on hand (i.e. canola or sunflower oil), a oil that works well with high heat dishes like stir-frying (i.e. peanut or sesame oil) and one with great flavour that works well in cold dishes (i.e. extra virgin olive oil or macadamia oil). And don’t forget to always use in moderation!