The facts on fat

Throw the word fat into conversation and you will trigger an avalanche of debate on the latest diets and nutrition trends. Which is why somewhere between the low-fat era of the 90’s and present-day chants of “fat is back”, there appears to be much confusion about the truth of the healthiest fats to eat as part of our diet.

Are fats important in our diets?

The fat food group contains more energy than carbohydrates and protein: 38kJ per gram of fat compared to 17kJ per gram each of carbohydrate and protein. Fat provides our bodies with the fat-soluble vitamins A, D, E and K and the essential fatty acids omega-3 and omega-6. Fat is involved in cell functioning, hormone production, immunity, and helps form a protective layer around our nervous system and organs. Healthy fats protect the heart by helping manage cholesterol levels and lower inflammation levels in the body, and recent evidence supports the role of omega-3 fats in mental illnesses such as Alzheimer’s disease and dementia.

Did you know that not all fats are the same?

Well-established evidence supports that not all fats are equal: monounsaturated fats should be eaten most often, polyunsaturated fats in moderation, and saturated fats and trans fats as little as possible. 

Monounsaturated fats (e.g. avocados, olives, olive oil, almonds, cashews) are super healthy fats that help to reduce total and bad LDL cholesterol and may increase good HDL cholesterol, which together have heart-protective benefits. In particular monounsaturated fats are beneficial when replacing the bad saturated fats. Monounsaturated fats also improve insulin functioning in the body by optimizing cell membrane structure and may reduce inflammation. For this reason, monounsaturated fats should be given preference over the other types of fat.

Omeag-3s and omega-6s are two essential fatty acids that fall into the polyunsaturated fat group. The body cannot make these fatty acids, which is why it is essential to get them from food. Omega-3s are very important for our bodies with good anti-inflammatory properties that are very beneficial to our health. The best omega-3 foods are fatty fish (e.g. salmon, trout, pilchards, mackerel, herring), followed  by linseed, chia seeds and flaxseeds. Focus on including omega-3s in your diet more often than you include omega-6s like sunflower oil.

Foods like coconut oil, butter, cream, cheese, bacon, chicken skin and fatty meat are examples of saturated fats. Strong evidence shows a link between high saturated fat diets and high LDL, the bad type of cholesterol. When following 120 000 participants for 24 years, replacing saturated fats with the same amount of heathier monounsaturated and polyunsaturated fats lowered the risk of heart disease by a considerable 15 and 25%, respectively. As a result, recommendations from international bodies are that saturated fats should be limited in the diet to less than 10% of total energy per day. Other unhealthy fats to be limited are trans fats: fats which undergo a chemical process called hydrogenation. During this process the fats change in chemical structure from oils normally liquid at room temperature to more solid fats such as in hard margarines.

How much fat should we be eating?

Fat contains more energy than carbohydrates and protein. Regardless of the type of fat, gram for gram, these fats have the same energy content which is why a focus on portion control is always important, whether healthy or not. We need fats but the type of fat we chose needs more focus. Emphasis should be on favouring the monounsaturated fats in olive oil, nuts and seeds, and fatty fish.

Low fat diets versus the Mediterranean diet: which is better for our health?

The low-fat diet from the 1990’s suggested that low intakes of fat are ideal for weight loss. It is interesting that a lot of research showed that despite eating less fat, this did not necessarily mean that people ate less energy (kilojoules) as  overeating of other foods still took place. Scientific support is strong for a Mediterranean style of eating, mimicking traditional dietary patterns of Mediterranean countries where healthy fats like olives, olive oil, avocados, nuts and seeds are encouraged. Rich in heart-healthy omega-3s (along with the generous consumption of fiber, nutrients and antioxidants from foods like fish and seafood, fruits, vegetables, legumes, moderate intakes of red wine and dairy, and limited red meat) this eating style is associated with longevity, reduced cancer risk, weight loss, and heart health.

In summary, it is important to remember that not all fats are created equal. Intentionally limiting good monounsaturated fats can negatively influence health. Favour mostly the fats that benefit our health (e.g. olives, avocado, nuts, seeds and their oils) and a reduce those fats that increase risk of disease (e.g. fatty red meat, chicken skin, butter, coconut oil). Whether a healthy fat or not, all fats have a high energy content (compared to carbohydrates or protein) you can control total kilojoules for weight loss by paying attention to your fat intake.

Written by Monique Piderit, RD (SA)

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