Fats are an important and often misunderstood part of our diet. Amongst other things, fat is a vital fuel that enables our bodies to carry out complex functions (such as cell production), as well as giving us the energy to keep us going through the day.
As scientific food-research has developed, it has become clear that there are good fats and bad fats – that the subject isn’t as black-and-white as traditionally thought. The dark side, and more generalised understanding of fat, is that excess consumption can lead to weight problems, cholesterol build up, serious heart disease, and potentially cancer. Fat isn’t all bad though, and with a little knowledge you can make decisions about the types of fats you and your family consume that will promote good health.
There are 2 main categories of fats – “Good”, unsaturated fats, and “bad,” saturated fats. Within these categories of good and bad fats are monounsaturated and polyunsaturated fats(good), and saturated and trans fats (bad). As a general rule unsaturated fats are found in fruits, vegetables, nuts and seeds. Saturated (bad) and trans (worse) fats are found in meat, dairy products, refined oils and processed foods.
As a simplified rule-of-thumb for good health and reducing risk of disease, saturated and trans fats should be minimized and replaced by unsaturated, good fats where possible. It is important to stress however, that there is no black and white rule; foods that contain saturated fat are often high in other nutrients so shouldn’t necessarily be cut out of your diet due to the fact they contain saturated fat. For example red-meat contains saturated fats, but is high in iron, magnesium and other essential nutrients. A better way to use the information, would be to consciously minimize the saturated fat intake, maybe by removing the fat from meat before cooking, or looking for leaner cuts.
Saturated fats are generally solid when at room temperature. They are found in dairy products like milk, butter and cheese, meats, as well as certain plants (coconut, palm oil, cocoa butter). Too much saturated fat causes the body to produce excess cholesterol, which leads to the production of bad, low density lipoproteins (LDL). LDL cholesterol is carried around the body and, when at high levels, can build up in arteries. This build up of cholesterol in the arteries can cause blockages which increases the risk of heart disease.
Trans fats are extremely bad for health and are increasingly common in today’s environment of processed and fast-foods. Trans fats are often identified as ‘hydrogenated’ on food packaging. Like saturated fats, trans fats increase LDL (bad) cholesterol levels and can increase the risk of heart and other diseases. Trans fats are often used in processed foods as they extend the shelf-life of foods. Trans fats are also commonly found in fast-food, products made using shortening (e.g bakery food), and refined vegetable oils.
Polyunsaturated fats are good fats generally found in vegetables. They are thought to reduce LDL (bad) cholesterol levels. Polyunsaturated-fat foods include (unrefined) vegetable oils, corn, sunflowers, sesame, walnuts, pumpkin seeds and fish. When on their own (e.g extracted as sesame oil), they are liquid at room temperature.
Monounsaturated fats, like polyunsaturated, are good for promoting health. They lower LDL cholesterol levels. Monounsaturated fats are high in Mediterranean diets, which studies show have a lower instance of fatal coronary heart disease – the most prevalent cause of preventable death. Monounsaturated fat foods include olives, almonds, avocado, peanuts, pecans, cashews and canola oil.
How to balance good and bad fats in a practical diet
Knowledge is power, and the important thing to remember about achieving a healthy diet is balance! By being aware of the good and bad points of the foods that make up your diet you can make it a habit to consciously act accordingly. Some foods that include saturated fats are an important part of a healthy diet (meat, dairy etc), as they provide essential minerals and nutrients, are an easy option, or kids want them in their school lunches (snack foods).
Being aware of the implications of good and bad fats and acting accordingly may mean buying lean meat; taking 5 minutes to strip the skin and fat off meat before cooking; or reducing serving size and supplementing your meal with a handful of nuts or olive oil over a salad. Simple adjustments like these to the way you eat have numerous health benefits including ongoing good health, reducing risk of disease, and can be used to encourage good food attitudes in children. At the supermarket you can look at the nutritional information on packaging and choose low-saturated, high-unsaturated fat options. Skim milk has the same nutritional benefits with a lot less saturated fat; snack foods and prepared meals often hugely differentiate in saturated and trans fat levels between brands. The same is true for many utility foods such as margarine, which often contain high levels of saturated and trans fats. Avocado or olive oil spreads, by comparison, taste much the same but with significantly lower levels of bad fats. Or even better, add avocado to your sandwich and remove the need for margarine all together.
Article References
Lyle, S. (2006). Discovering fruit nuts: A comprehensive guide to the cultivation, uses and health benefits of over 300 food-producing plants. Auckland, NZ: David Bateman.
Penny, S. (2004). Food matters: A guide to healthy eating supplements. Wellington, NZ: Massey University, Institute of Food, Nutrition and Human Health.
Ternus, M, E., Lapsley, K., Geiger, C, J. (2009). Health benefits of tree nuts. In F. Shahidi C. Alasalvar (Eds.), Tree nuts: Composition, phytochemicals, and health effects. CRC Press.