Trans Fats: the new bad fat
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Nutritionist Catherine Saxelby explains what trans fat is and why we should avoid them. |
What are trans fats?
Also known as trans fatty acids, trans fat is chemically an unsaturated fat, but the molecules are “rearranged” so they behave like a saturated fat. Trans fats are formed when hydrogen is added to an unsaturated fat through a process called hydrogenation. Hydrogenation makes the fat more solid and less likely to spoil. This process can occur naturally in some animals or industrially in food manufacture.
Where are they found?
Natural trans fats are created in the rumen (forestomach) of cows, sheep and goats by microorganisms. Therefore, beef, lamb and dairy products contain small amounts of trans fat. There is no evidence to suggest that natural forms of trans fats are bad. It’s the manufactured trans fats you need to worry about and these are found in:
- Deep-fried takeaway food such as chips, French fries, nuggets and wedges
- Solid cooking margarines
- Microwave popcorn
- Donuts
- Baked goods such as meat pies, sausage rolls and croissants
- Packet cake mixes
- Manufactured cakes and biscuits
- Gravy powder
- Instant noodles
- Frozen foods including fish fingers and crumbed chicken.
Why are they bad?
Trans fats are bad for your heart, as they raise your total and LDL (“bad”) cholesterol in the same way saturated fat does. Trans fat also seems to lower your HDL (“good”) cholesterol, which protects against heart disease. Health professionals recommend limiting your intake of both trans and saturated fat.
How to avoid trans fat
- Avoid deep-fried fast food and takeaways
- Avoid commercial cakes, biscuits and pies. Instead, make them at home so you can control the type of fat used
- Choose a spread that is low in saturated and trans fat
- Choose filo pastry instead of puff or shortcrust pastry.
Looking for trans fat on the label
Food manufacturers in Australia are not required to include trans fat on the label, unless they make a claim about cholesterol (“cholesterol free”) or unsaturated fat (“low in saturated fat”). If no claim is made, manufacturers only need to show the amount of total and saturated fat.
Foods that are “trans fat free” must contain no detectable trans fat, where as those “low in trans fat” must contain at least 25 percent less trans fat than the regular variety. Seeing either “hydrogenated” or “partially hydrogenated” in the ingredients list means the product contains trans fat, but this won’t tell you how much.
Unlike the US, we have a relatively low intake of trans fat in Australia because our food industry uses different fats particularly palm oil or beef tallow. These fats are typically low in trans fat but high in saturated fat.
So while trans fats aren’t good for your health, in Australia it’s more important to base your food choice on cutting back on saturated rather than trans fats. This is because saturated fats are still the predominant ‘bad fat’ in the Australian diet today.