Chewing the Fat: the good, the bad & the greasy


It’s one of the longest-running nutrition debates and it has us saying – “what the FAT?” Ah, yes. Fat. Should we eat it? Should we avoid it? What about coconut oil? Is full-fat dairy better or worse?

For the longest time we were told to avoid fat and to choose low-fat where possible. There are so many opinions and mixed messages around this macronutrient, even nutrition experts don’t ever seem to agree. Confusing, much!?

Nutrition is an ever-evolving science – the more research that’s done, the more we know.

The latest evidence suggests that we should be including fats in our diets – the key is choosing the right type and amount!

Why do we need fat?

In addition to regulating cholesterol levels and maintaining heart health, fat also provides our bodies with energy, keeps us warm and protects vital organs like the heart, kidneys and liver. Fat is important for proper brain function – in fact, did you know that 60% of your brain is made out of fat.

Fat is vital for the production and regulation of hormones such as leption (the satiety hormone) and reproductive hormones – women who don’t have enough fat may lose their period and may become infertile.

An adequate supply of fats also helps keep your skin healthy and hair shiny. And it’s important in helping our bodies absorb nutrients, in particular the fat soluble vitamins – A, D, E, K.   

Essential fatty acids (omega-3 and omega-6 fatty acids) help regular blood clotting and control inflammation in joints, bones and other tissues.  

Adding healthy fat to your meal will also slow down the digestion of that meal, helping you to feel fuller for longer.

Phew! Is there anything this macronutrient doesn’t do!

So, yes, we definitely need fat in our diets but we need to choose the right type because different fats will have a different effect on your body and most importantly your heart health.

Cholesterol – The Good and The Bad

Before we launch into the story around fats, we need to take a closer look at cholesterol because the different fats found in food will have a direct impact on your cholesterol levels.

Cholesterol is found in all cells of the body – it’s an important part of cell membrane structure. What’s more – your brain is 25% cholesterol and cholesterol is used by your body to make Vitamin D, Glucocorticoids (a steroid that plays a role in inflammation) and sex hormones (progesterone, testosterone, estrogen). So it’s kinda a big player!

The great thing is that our bodies are able to make the amount of cholesterol they need. In fact, according to Harvard Medical School, ‘your liver and intestines make about 80% of the cholesterol we need to stay healthy’. Only about 20% comes from the food that we eat.

We have different types of cholesterol in our blood. In general, the two types are classified as good cholesterol, which is known as HDL cholesterol and bad cholesterol which is typically LDL cholesterol.

It’s important that what we eat supports the production of good cholesterol rather than the bad – good cholesterol is heart protective, while bad cholesterol leads to clogged arteries and increases your risk of heart disease and stroke.

Supporting healthy cholesterol levels can be done by eating a diet rich in unsaturated fats like fish, avocados, nuts and seeds, oils such as olive oil, and leafy greens.   

On the flip side, according to the American Heart Association, a diet high in saturated and trans fats (more on the types of fats later) ‘causes your liver to make more cholesterol than it otherwise would and for some people this added production means they go from normal cholesterol levels to a level that’s unhealthy’.  

What are the types of fat in our food?

The food we eat will generally contains one (or a combination) of the four types of fat – monounsaturated fats, polyunsaturated fats, saturated fats and trans fats. Some are good for us, some not so good and some are downright nasty!

  • The Good – Unsaturated Fats (Mono- and Polyunsaturated fats)  

Fats that are well-known to have positive health benefits and that are good for us and our hearts are unsaturated fats – monounsaturated and polyunsaturated fats.

These fats help to raise good cholesterol levels in the blood (HDL-cholesterol) while decreasing the bad type (LDL-cholesterol). This positive effect on blood cholesterol helps to reduce your risk of heart disease (which results from clogged arteries) and stroke.

Polyunsaturated fats can be further broken down into omega-3 and omega-6 fatty acids. These are essential fatty acids (meaning you must get them from your diet because your body can’t make them) with key roles in maintaining heart health, inflammation, immune function and blood pressure control.

The key with the essential fatty acids is getting the ratio right. Make sure your diet is skewed towards the omega-3’s because a diet too high in omega-6 fatty acids (common in the Western diet) leads to inflammation and increased blood pressure.    

Where do I find unsaturated fats?

Monounsaturated fats are found in avocado, nuts (peanuts, hazelnuts, cashews and almonds) and olive oil. Polyunsaturated fats are found in fish, seafood, nuts (walnuts and Brazil nuts) and seeds.

  • The Bad – Saturated Fats

It has long been known that saturated fats raise the risk of heart disease and stroke because they raise the bad cholesterol (aka LDL cholesterol) levels.

Where do I find unsaturated fats?

Saturated fats are commonly found in commercial products such as biscuits and pastries, and takeaway foods. They are also found in full fat dairy (yoghurt, cheese, cream), butter and meat products, most deep-fried foods, coconut oil and palm oil.

A quick word about coconut oil

Over recent years coconut oil has been touted as the miracle cure for almost everything! From having antibacterial properties, controlling blood sugar levels to boosting metabolism it seems coconut oil is some sort of an elixir!

But hold the train.

Before you head to your local health food store or the healthy section of your local supermarket, it’s important to remember that coconut oil is mainly saturated fat. While it might not be ‘the devil’ due to the various benefits of the particular saturated fats found in this oil, its antioxidant properties, and its stability when used in cooking, it’s not a miracle cure and you should use it sparingly.

Don’t lather everything in the stuff because too much saturated fat is linked with raised cholesterol levels. Moderation and use in combination with other, unsaturated oils, is certainly the key here.     

  • The Down Right Nasty – Trans Fats

While we do get a small amount of trans fats in animal foods, particularly milk, cheese, beef and lamb, they are mostly created during the manufacture of commercial baked goods such as pies, pastries, cakes, biscuits and buns through a process called Hydrogenation.

It’s important to limit (or avoid if possible) these fats because not only do they raise bad cholesterol levels thereby increase your risk of heart disease and stroke, they also lower good cholesterol levels – this makes them doubly bad!

How much fat should I be eating?

Generally speaking (and of course this will vary between individuals, individual goals and whether or not you’re on a specific diet such as the Keto Diet), it is recommended that fat should make up no more than ~20-35% of your total caloric intake. This means that if you consume 8000kJ/day, you should be eating no more than about ~43-76g of total fat per day.

It’s also recommended that you should limit your intake of saturated fats to no more than about 10% of your total energy (kJ) intake or about ~22g if you’re consuming an 8000kJ diet.

Key Takeaways

  • Including healthy fats in your diet is important for overall health – don’t fear fat!
  • The key is including mainly healthy fats such as mono- and polyunsaturated fats and limiting saturated fats
  • Where possible try to limit or avoid foods high in trans fats

If you’re concerned about how much fat your eating and wondering how this is impacting on your cholesterol levels and heart health, get in touch! I’d love to chat and help! 🙂

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