The F-word
Fat is an essential part of a balanced diet. Here’s the skinny on how it helps you stay healthy.
Ask any health expert and they’ll tell you that fat is essential for a healthy balanced diet. Whether it’s the National Health Service (NHS), the American Heart Association or Australia’s National Health and Medical Research Council, everyone agrees that we all need at least some fat in our diets.
Besides being a source of energy, lipids help the body to build cell membranes, protect nerve cells and assist with the absorption of vitamins A, D and E. On a more tangible level, they’re essential for blood clotting, reducing inflammation and enabling muscle movement. They also give skin a healthy glow.
Fat: the good, the bad and the ugly
All fats are chemically similar. Whether saturated, unsaturated or trans, they are made up of a chain of carbon atoms bonded by hydrogen atoms. The differences between them are due to variances in the length and shape of these chains, as well the number of connected carbon and hydrogen atoms.
The most broad distinction when it comes to fats is between saturated and unsaturated fats. While saturated fat is an umbrella term for a variety of lipids, unsaturated fat can be divided into monounsaturated, polyunsaturated and trans-unsaturated (trans) fat.
Saturated fat
With only single bonds in the carbon chain, all of the remaining bonds on the carbon atoms in saturated fats are occupied – or saturated – by hydrogen atoms. Aside from giving this lipid its name, the structure is also the reason why saturated fats are solid at room temperature.
Animal products like red meat and dairy have the highest concentrations. But plant products like coconut oil, palm oil and cocoa are rich in these solid fats, too. Even products that are touted as being sources of unsaturated fat, for example olive oil, nuts and avocados, contain some saturated fat.
Although healthcare practitioners have long advised that we avoid saturated fat, new research indicates that we should rather be more discerning about the type of saturated fat we consume. As foods contain a variety of nutrient and non-nutrient components (and other fats) the source of the solid fats will influence how they affect our heart health.
There is also increasing evidence that there is no link between any important health outcome, including cancer, heart disease and weight gain, and the overall percentage of calories from fat.
Unsaturated fat
The carbon chain in unsaturated fats has at least one double bond between carbon atoms. This structure means that fewer hydrogen atoms can attach to the double-bond carbons, making these healthy fats unsaturated and liquid at room temperature.
Monounsaturated fat
As the ‘mono’ in the name suggests, these fats have only one double bond in their carbon chains. Incorporating them into your diet can lower your LDL (bad) cholesterol while maintaining HDL (good) cholesterol levels, and may even be beneficial in controlling insulin and blood sugar levels. Seeds, nuts, avocados, peanut oil, canola oil and olive oil are all great sources of monounsaturated fats.
Polyunsaturated fat
Known as essential fats, our bodies can’t synthesise polyunsaturated fats and we must therefore absorb them from the food we eat. These multi-bond carbon molecules are responsible for body functions like blood clotting, muscle movement and reducing inflammation. Missing out on them is guaranteed to have adverse effects.
Omega-3 – likely the most famous fat of them all – and omega-6 fatty acids are the two main polyunsaturated fats. While both have been linked to protection against heart disease, omega-3 has a slew of additional benefits, including lowering blood pressure, increasing good cholesterol and lessening arthritic inflammation.
Vegetable oils, like sunflower, soybean, safflower and walnut, are all rich in omega-6 fatty acids, while fatty fish (e.g. salmon, mackerel and sardines), soybean and canola oil, walnuts, and flaxseeds are good sources of omega-3.
Trans fat
Although technically an unsaturated fat (it’s the by-product of a process called hydrogenation, which turns healthy oils into solids), trans fat deserves a category of its own. Unlike saturated fat, there’s no debate around the health benefits of trans fats. And that’s because there are none.
Trace amounts of trans fats are found in dairy products, beef, lamb and pork. But the real problem is items with a high concentration of trans fat. Think vegetable shortening, fries, pizza, chips and baked goods, along with other pre-packaged and processed foods.
Foods rich in trans fats increase the levels of LDL cholesterol while decreasing HDL cholesterol, which is why they’re linked to heart disease, stroke, diabetes and a slew of other chronic illnesses. Stay as far away from them as possible.
How you incorporate fats into your diet will depend on your particular body chemistry, health concerns and caloric needs. Like many other things in life, fats can’t simply be categorised as either ‘good’ or ‘bad’. There’s no harm in drizzling some olive oil on your homemade bread or tucking into a fatty steak – just don’t dip your hands into chip packets or pizza boxes.
