For years, popular culture denounced dietary fat as weight-loss enemy No. 1. Public opinion has finally shifted back in favour of fat—which is good news, since that view actually aligns with nutrition science. Along with carbohydrates and protein, dietary fat is a macronutrient that provides energy for the body. You can’t thrive without it! “Your body needs fat to absorb vitamins A, D, E, and K, as well as antioxidants like lycopene and beta-carotene,” says registered dietitian Alissa Rumsey.
Fat also helps meals feel more satisfying—as it travels through the digestive system, fat stimulates the release of a hormone called cholecystokinin, which sends fullness signals to the brain. Fat also affects the flavour of a dish: “Fat tenderises and lubricates, which enhances a food’s flavour and gives it a velvety texture,” says registered dietitian and nutritionist Patricia Bannan.
The Australian Dietary Guidelines recommend that fat should make up 20–35% of total energy intake to support optimal health—with no more than 10% of this coming from saturated fat. However the types of fat you eat do matter, with some kinds of fat being better for the body than others. Here’s a closer look at healthy versus unhealthy fats, along with some nutritious food sources to consider putting on your plate.
Understanding ‘healthy’ vs. ‘unhealthy’ fats
Unsaturated fat
This is the ‘healthy’ fat most experts recommend consuming in your diet. Unsaturated fat comes in two forms: monounsaturated and polyunsaturated. Both play a role in building and maintaining cells. Unsaturated fats also help control levels of harmful LDL cholesterol, which can lower a person’s risk of developing heart disease or experiencing a stroke.
- Monounsaturated fats are found in plant-based oils such as olive and canola oil. Avocados, olives, peanut butter and some nuts and seeds also contain monounsaturated fats.
- Polyunsaturated fats are found in sunflower seeds, as well as oils derived from soybean and sunflower. Omega-3 and omega-6 fatty acids, also part of the polyunsaturated category, are found in oily fish such as salmon, tuna, sardines, trout and herring, as well as canola oil, walnuts, and flaxseed (linseed). Consuming foods that contain omega-3 and omega-6 fatty acids is important as they are vital for brain function and cell growth, and our bodies are unable to make these types of fats.
Saturated fat
Saturated fat is one to consider limiting. Found primarily in animal sources—such as meat, full-fat dairy and butter—as well as in coconut and palm oil and discretionary foods like ice-cream, pastries and sweets, saturated fat can increase blood levels of LDL cholesterol when consumed in high amounts.
Trans fat
Trans fat is one you may wish to avoid as much as possible. It increases LDL cholesterol and lowers beneficial HDL cholesterol, which likely explains its link to heart disease, stroke and type 2 diabetes. Trans fats are not as common in Australia or New Zealand as they are in other countries. Food Standards Australia New Zealand says the industry generally maintains a low trans fat content, therefore it is not compulsory for manufacturers to declare trans fat content on packaging. Foods high in trans fats may include baked goods (pastries, cakes, biscuits), deep-fried foods and takeaway/fast foods such as burgers, hot chips. Small amounts also occur naturally in some meat and dairy products.
Cholesterol
Cholesterol is a fat-like substance that is only found in animal products such as meat, eggs, and dairy. Your body needs some cholesterol to produce vitamin D and hormones, and to keep cells healthy. And despite its negative reputation, research shows that dietary cholesterol doesn’t increase blood cholesterol levels. In fact, consuming large amounts of foods that contain saturated and trans fats has a greater impact on blood cholesterol levels.
Healthy-fat foods: 8 foods that contain unsaturated fats
“To get more satisfaction and nutritional benefit out of your meals, try to incorporate healthy fats into every one,” advises Lauren Antonucci, a registered dietitian and nutritionist. Here are some tasty options to try:
1. Avocado
Avocados contain monounsaturated and polyunsaturated fats. They’re also high in fibre, and are full of nutrients including folate, magnesium, potassium and vitamins B, C, E and K. Avocado’s creamy texture and delicious taste makes it a perfect addition to a salad or used in place of mayo or spreads like butter on a sandwich.
2. Eggs
One large egg (~60g) provides nearly 6 grams of fat, with the bulk (~3 g) being unsaturated. Eggs are also rich in protein, the essential nutrients vitamins A, D, and B12, and brain-boosting choline, which plays a role in memory and mood. Eggs are naturally high in cholesterol, but for most healthy people, that’s not a concern.
RELATED: Are eggs good for you?
3. Oily fish
Salmon, cod, mackerel, anchovies, herring and tuna are high in omega-3 fatty acids, which reduce inflammation and may protect the heart. In a research review published in the Journal of the American Medical Association, eating one or two servings of oily fish per week was associated with a 36% lower risk of dying of heart disease. A few simple recipes can help you get more seafood into your regular rotation.
4. Nuts
Nuts are full of healthy unsaturated fats, as well as protein, fibre and vitamin E. Walnuts have an added bonus of also being high in omega-3 fatty acids. Whether you favour almonds and cashews, pecans or pistachios, keep the portion size in mind; a serving of nuts is 30g—about 20 almonds.
5. Olive oil
Olive oil is predominantly made up of a monounsaturated fat called oleic acid, which may help lower blood pressure and reduce inflammation. It’s also got loads of antioxidants, along with vitamins E and K. When selecting, opt for an Australian extra-virgin olive oil. Extra-virgin olive oil is made from pure, cold-pressed olives and is the least processed form of olive oil, whereas regular olive oil is a blend, including both cold-pressed and processed oils.
6. Seeds
Seeds are small but mighty when it comes to nutrition. They’re high in unsaturated fat, fibre, antioxidants, calcium and protein. Chia seeds and flaxseeds, in particular, are great sources of omega-3 fatty acids, and can be simply added to your morning cereal, yoghurt snack or even blended in a smoothie. Chia seeds are also the star ingredient of the popular breakfast pudding like this chai pudding with caramelised banana recipe.
7. Nut and seed butters
Most of the fat in seed and nut butters comes from the healthy monounsaturated and polyunsaturated kinds. These spreadables are also a delicious source of protein, fibre, vitamins, minerals and phytochemicals.
8. Olives
Just like their oil, olives are high in vitamin E and other powerful antioxidants. They also contain healthy, polyunsaturated and monounsaturated fats that help reduce inflammation. They’re delicious as a snack or in a Mediterranean dish like these Mediterranean eggplant rolls.
Healthy fats and weight loss
The basic rule always applies: a calorie (kilojoule) deficit is required for losing weight. And it’s totally possible that eating foods containing healthy unsaturated fats could help make that happen. “Eating more healthy fats and fewer highly processed fats may leave you feeling more satisfied and better nourished, which can make it easier for you to potentially lose weight,” St. Pierre says. Indeed, research suggests that healthy fats may help people feel more satisfied with modest portions. A small study published in the journal Obesity found that a diet rich in polyunsaturated fat was linked to increased secretion of the appetite-suppressing hormone PYY (peptide tyrosine).
Higher-fat diets
Some research suggests that high-fat, low-carb diets are more effective for short-term weight loss than high-carb, low-fat diets. But that’s a comparison of two extremes. Most experts, including those on the WeightWatchers® Science Team, agree that a balanced and liveable mix of fat, carbs, and protein most strongly supports healthy weight management over time. “The more restrictive a diet becomes, the harder it is to follow in the long-term—and it’s consistency that matters in the end,” St. Pierre says.
The upshot: Are healthy fats fact or fiction?
In summary, fat is an important part of a healthy diet. In addition to being necessary for the absorption of certain key vitamins (A, D, E and K), healthy fat can help reduce inflammation, increase satiety, and support other aspects of wellbeing. While WW steers clear of declaring specific foods ‘good’ or ‘bad,’ research has consistently demonstrated that different types of fat affect the body in different ways. Dietary patterns that emphasise unsaturated fats are associated with health-protective benefits, while dietary patterns high in saturated and trans fats are associated with an increased risk of developing certain diseases. Learning to identify and incorporate healthy unsaturated fats into your diet can be a simple way to help support your wellness goals over time.
