While all fats are high in calories and contribute to weight gain, some are necessary for our health. It's important to be aware of the different types, and how they affect us.
Studies have shown that eating as little as 5 grams of trans fat a day can increase the risk of coronary heart disease by 25%.
Effect on cholesterol levels
Too much cholesterol in the blood will block your coronary arteries, increasing the risk of heart disease.
Eating some fats can improve (i.e. lower) the level of cholesterol in our blood, while eating others makes it worse. In particular they can affect the levels of good cholesterol (high-density lipoprotein or HDL) and bad cholesterol (low-density lipoprotein, or LDL).
- Trans fats
Good nutrition = moderation
For a healthy heart, enjoy a balanced and wide variety of foods every day. Include polyunsaturated and monounsaturated fats in moderation, and aim to minimise saturated and trans fats.
Eaten in moderation, polyunsaturated fat may help to lower the level of bad cholesterol. It also includes essential fats that your body can't produce, such as omega-3 and omega-6.
Omega-3 food sources include:
- oily fish (e.g. salmon, mackerel, herring, sardines)
- white fish
- dark green leafy vegetables
- fortified foods such as bread
Omega-6 food sources include:
- safflower, grapeseed, sunflower and corn oils
- walnuts, hazelnuts, brazil nuts
- seeds, e.g. sunflower, safflower, pumpkin and sesame
- soy products - tofu, soy milk
- polyunsaturated margarine.
Monounsaturated fats can help lower blood cholesterol, but not to the same extent as polyunsaturated fats.
Food sources include:
- peanuts, walnuts, almonds, cashew nuts
- seeds, e.g. sesame, pumpkin
- lean red meat, chicken, fish, venison, kangaroo
- olive, peanut and canola oils
- monounsaturated margarines.
These are found mainly in animal products. Eating saturated fats raises the total level of cholesterol in your blood, as well as the level of LDL (bad cholesterol). This contributes to problems with blocked arteries.
- meat, including lamb, pork, fatty beef, processed meats
- chicken with skin
- dairy products such as whole-fat milk, cream, butter, lard, hard cheese
- many baked goods and fried foods
- palm oil, palm kernel oil, and coconut products - oil, cream and milk.
Trans fats are produced during the process of hydrogenation – adding hydrogen to vegetable oils to make them more solid. This gives food a better taste and texture, and is used in producing fried foods and commercially baked goods.
Like saturated fats, trans fats have a negative effect on our blood-cholesterol levels. They raise total cholesterol, increase the bad cholesterol and lower good cholesterol.
Trans fats also occur naturally in dairy products and meats.
Food sources include:
- beef and lamb fat
- full-cream dairy products and butter
- cakes, pies, biscuits, crackers
- pizza, fries, doughnuts
- potato chips, corn chips, popcorn.
Tips to avoid trans fats
- Choose low-fat dairy products.
- Choose lean cuts of meat.
- Trim visible fat off meat before cooking.
- Choose a margarine with trans fat levels of less than 1%.