Fat

Types of fat

The main types of fat are saturated, polyunsaturated, monounsaturated, and trans fats. All these different types of fat contain the same amount of energy per gram, however, they have different effects on our heart and overall health.

Saturated fat 

Saturated fat increases total cholesterol by increasing the ‘bad’ LDL cholesterol, so it should be eaten in the smallest amounts.We should aim to reduce saturated, and choose monounsaturated and polyunsaturated fats instead.

Sources: Butter, cheese, meat fat, ghee, meat products (sausages, hamburgers), full-fat milk and yoghurt, pies, pastries, biscuits, cakes, lard, dripping, hard margarines and baking fats, coconut and palm oil.

Monounsaturated fats 

Monounsaturated fats appear to protect against heart disease, by increasing the levels of ‘good’ HDL cholesterol.

Sources: olive oil, avocado and avocado oil, canola oil, nuts (pistachio, almonds, hazelnuts, macadamia, cashew, pecan, peanut) and the oils from these nuts.

Polyunsaturated fats 

Polyunsaturated fats can help lower your LDL (bad) cholesterol. Polyunsaturated fats include the essential omega–3 and omega–6 fats. They are essential as we have to get them in our diet our body cannot make them.

Omega-3 fats have a positive impact on heart health and an important role in brain and eye function. Omega-3 can be further divided into two forms:

• Long-chain omega-3 which includes eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)
• Sources: Oily fish (salmon, mackerel, herring, trout), mussels
• Short-chain omega-3 called alpha-linoleic acid (ALA)
• Sources: mostly found in plant foods e.g., walnuts, canola oil, soybean, flaxseed, and their oils

Your body can convert the short chain ALA into long-chain omega-3 fatty acids for the body to use. However, the conversion rate is relatively low.

Omega-6 fats are necessary for the growth and the synthesis of hormone-type compounds. Sources: sunflower seeds, wheat germ, sesame, walnuts, soybean, corn, and their oils, certain margarines.

Trans fats 

Trans fat are a very harmful type of fat (even more so than saturated fat) as it not only increases ‘bad’ LDL cholesterol, but it also decreases ‘good’ HDL cholesterol.

Sources:

• Artificial trans-fats are formed when liquid vegetable oils are processed with hydrogen to make them into solid, shelf-stable products such as shortenings and margarines. This process is called partial hydrogenation. However, because trans fats are so harmful, food manufacturers now use a different process called ‘full hydrogenation’ which does not produce much trans-fat. Therefore, most margarine and shortenings nowadays do not contain any significant amount of trans-fat.
• Trace amounts can be produced in the heating and frying of oils at high temperatures.
• Trace amounts of ‘naturally occurring’ trans-fat are also found naturally in beef, mutton, lamb and dairy fat.

There is no ban on trans-fat in New Zealand, however, because of the change in manufacturing practices, we eat below the recommended levels of trans fat suggested by the World Health Organisation (NZFSA 2006 and 2021). Most of the trans-fatty acids we eat are from butter, cheese, and meat. Note that, since 2018, the USA’s FDA has banned the addition of trans fat to food products (FDA, 2018)

While we in NZ have reduced our trans-fat intake, we are still eating too much-saturated fat, and need to try to reduce this as a population.

For more information read Fats and Oils – what does science really tell us to eat?

How much fat do we need?

It is recommended that adults get

• between 20–35% of their total energy from total fat (Nutrient Reference Values, 2014). This may seem like a lot but keep in mind fat is energy dense.
• Less than 1% of our total energy from trans fat
• Less than 10% of total energy from saturated fat

For more values visit Nutrient Reference Value: Fats: Total fat and fatty acids.

Note that infants and toddlers need a higher proportion of their energy intake to come from fat. Breastmilk (and formula) is relatively high in fat. From the age of 12 months, it is safe to provide cow’s milk to your infant, if you choose to do so, ensure that it’s full-fat milk (dark blue top). After 24 months, if they are growing well, it is safe to switch them to reduced fat milk (Ministry of Health, 2021). Read our Infant and Toddler’s page for more info.

NZNF White Paper – Dietary Fats & Oils

Read our report on Dietary Fats & oils

Dietary fats play an important role as a source of energy, as structural components and as carriers of other dietary components including fat-soluble vitamins. However, the role of different dietary fats and oils in human nutrition is one of the most complex and controversial areas of investigation in nutrition science. Experts agree evidence does not suggest total fat intake has significant effects on the risk of coronary heart disease (CHD) or cancers. The primary concern and importance is the potential relationship between total dietary fats and body weight, as overweight and obesity are risk factors for both cardiovascular disease (CVD) and cancer.