Joanna is a registered nutritionist and dietician with a PhD in nutritional science from the University of Sydney. She is the resident nutrition expert for Channel 9’s Today Show, contributor to magazines including Life Etc and Slimming & Health and author of numerous books including Inner Health Outer Beauty, Star Foods and the Low GI Diet.
Fats are probably the most talked-about aspect of nutrition and arguably the most controversial. Studies conducted in the 50s, 60s and early 70s linked high fat intakes to heart disease, certain cancers and obesity. And so we entered the low fat era of dietary thinking. We were encouraged to examine the fat content of everything we ate and this became the sole criteria for assessing the healthfulness of a food.
I remember being a teenager and demolishing an entire French baguette and thinking that was OK — it wasn’t fattening because it was virtually fat-free! It seems crazy now but many are still stuck in the low-fat rut and wonder why they can’t lose weight, or struggle with trying to stick with the plan. Others have embraced the high-protein diet way of thinking and eat as much fat as they want to, believing that it’s not fat that is making us fat, but carbs… and so off we head down yet another restrictive, difficult to follow dietary path. The truth about fats is they can do both harm and good — it’s all down to which ones you are eating.
There are essentially three main types of fat: saturated, monounsaturated and polyunsaturated. Although there is a mixture of all different fats in any one food, we tend to label them according to the one that predominates. We can speak generally about these three fat families.
Saturated fats are thought of as the baddies. They raise blood cholesterol levels and therefore are thought to increase the risk of heart disease. More recent research suggests that saturated fats may also be metabolised differently in the body to other fats, such that they are harder to burn as fuel and easier to store as body fat. In this way a high intake of saturated fat may be contributing to problems with body fat control. Most saturated fat is found in foods with animal origin. This includes full fat dairy products, fatty meat, paté, butter and products made from it including biscuits, cakes, pastries and croissants. Generally speaking we want to eat less of these things to lower our saturated fat intake.
There are also two major plant fats that are also major sources of saturated fat — palm oil, a cheap commercial oil and therefore used ubiquitously in food manufacturing, and coconut products including the oil, milk and cream. I try to avoid palm oil when I can because not only is highly saturated, but also highly refined and not a good quality fat.
However coconut is more controversial. Most government health sites and many dietitians still list it on the “fats to avoid” list. Yet search the internet and you’ll find numerous sites espousing the health benefits of this tropical plant. These seemingly conflicting views come from the oversimplification of lumping all saturated fats together. In fact there are many different types within the category and those found in coconut are not the same as in animal foods. Coconut is rich in medium-chain triglycerides or MCTs for short. These are readily burned as fuel and do not raise cholesterol as other saturated fats do. The jury may still be out but I am sold on the benefits of quality coconut products used in appropriate quantities. Coconut oil is very stable in cooking and so is perfect for stir-frying and high heat cooking, and look for a coconut milk with no additives (read the ingredients list to be sure as most supermarket varieties do).
Monounsaturated fats dominate in olive oil, many nuts including peanuts and therefore peanut butter, and avocado. Eggs are not usually labelled as monounsaturated fat sources, yet it is the dominant fat providing about half of the fat present. In general these are good fats to eat. When used in place of saturated fats they do an excellent job of lowering ‘bad’ cholesterol levels. They are also far more stable in cooking than the polyunsaturated fats, making them less likely to form harmful fats at high heat or to go rancid in storage. Those Mediterranean countries have much right in their diet and I follow their example and make olive oil a staple in my pantry.
The polyunsaturated fats include the essential fatty acids that we must eat because we cannot make them in our body. Polyunsaturated fats reduce cholesterol levels and are generally thought of as good for us. However they are far less robust than the other fats. They oxidise easily on exposure to light and/or heat — for this reason you need to buy your oils in small, dark bottles and keep them in a cool place.
Within the polyunsaturated fats there are two further families with very different effects — the omega-6 and the omega-3 fats. Omega-6 fats are found in seeds, many nuts and oils such as sunflower and soybean. The widespread use of these oils in recent years has meant an increase in our diet and this is not good. By having too much omega-6 we prevent our bodies from absorbing and using sufficient omega-3s. You needn’t avoid the omega-6s but my advice is to get them from whole seeds and nuts, rather than from using the oils.
The omega-3s are the really good guys and the ones most of us lack. Omega-3 fats:
It may seem fanciful to think one group of fats can have such wide-ranging effects, but not when you consider that fat is in the makeup of almost every cell in the body.
Omega-3s are found primarily in oily fish, seafood, free-range eggs (foraging on pasture) and meat from grass-fed animals, especially game meats. There are also an increasing number of omega-3 fortified foods that can play an important part in stepping up your intake, particularly since few people eat enough fish. You will also find omega-3s in certain plant foods including flaxseed oil (in the fridge at most health food stores), leafy greens and walnuts. But these are short chain as opposed to the long chain omega-3s found in fish and, although valuable, they don’t quite do the same thing.
My advice is unless you are vegetarian, aim to have an oily fish or seafood at least twice a week, and take a good quality fish oil supplement. The latest recommendations from the NHMRC are for a daily intake of long chain omega-3s of 430mg for women and 610mg for men. Read the back of the supplement label to be sure you are reaching this target.
And finally whatever oil you choose to use at home, be sure to look for one that is unrefined and gently extracted — cold pressed oils are the best. Yes these are more expensive but the cheap supermarket oils are chemically refined and usually subjected to high heat and other refinement procedures that affect the nutritional quality. Skip them and go for a little of the real thing — the taste is infinitely better and your body and health will be all the better for it.
|Fish, especially oily fish such as salmon, trout, sardines, mackerel & herring||Seafood – oysters, mussels, squid & scallops all have more than 300mg omega-3/100g||Lean meats, preferably grass-fed or game meats||Omega-3 rich free range eggs||Nuts & seeds||Leafy greens & seaweed||Avocado||Olives & olive oil|
|Fatty meat & meat products such as sausages, burgers & salami||Full fat dairy products & butter||Products containing palm oil (read ingredients list)||Commercial croissants, pastries, cakes, biscuits||Commercial deep fried & fast food|