By Kim Hofmann RD(SA)

Recently I’ve had many clients come to see me because they are so confused about healthy eating.  When they read about fats on the internet, they don’t know what to believe anymore.  Many people still believe fats are ‘bad’, but there is also confusion as diets high in fat have managed to control diabetes and have helped with weight loss.  So are fats good or bad, and should we be incorporating them into our diet?

To start with let’s look at the different types of fat.  There are 3 types, namely unsaturated, saturated and trans fats.

Unsaturated fats are predominantly the plant fats, such as nuts, seeds, avocado, olives, as well as fatty fish.  Saturated fats are the animal fats, such as butter, lard, fat in red meat, as well as coconut and palm kernel.  And trans fats are man-made fats – they are generally found in foods that have used unsaturated fats and have been exposed to high temperatures.  This includes fried foods, as well as cakes, biscuits, chips etc.

A recent study, which followed the participants for more than three decades, showed that eating more unsaturated fat is associated with lower mortality, specifically a lower risk of death from cardiovascular disease, cancer, neurodegenerative disease, and respiratory disease.

The researchers found that different types of dietary fat had different links with mortality:

  • Trans fats are the most harmful for our health – every 2% increase in intake of trans fat was associated with a 16% higher chance of premature death
  • A higher intake of saturated fat was linked with a higher mortality rate – every 5% increase in saturated fat intake was associated with an 8% higher risk of overall mortality
  • A high intake of unsaturated fats – both polyunsaturated and monounsaturated – was associated with between 11% and 19% lower overall mortality

Replacing saturated fats with unsaturated fats gives substantial health benefits

Interestingly, within the study, those that replaced carbohydrates with saturated fats (i.e. ate less carbohydrates and more saturated fat) had a higher mortality risk, although this was only slightly higher when the carbohydrates were primarily refined starch and sugar.  Refined carbohydrates and sugar have a similar influence on mortality risk as saturated fat.  When the whole grain, high fibre starches were replaced with saturated fat the mortality risk was far higher.

The take away message from this study is that it is good to have a higher fat diet, as long as the fat you are adding comes from plant sources and fatty fish.  Together with the plant fats, you should also eat lots of fruit and vegetables, incorporate legumes and wholegrain starches as well as eat lean protein, fatty fish and low fat dairy products.