Fats – the good, the bad and in between

How to be smart about the fats in your diet

There’s a lot of talk about fat – some say to avoid it, others to eat more of it, while the rest of us probably aim for the middle ground. But here’s the point – not all fats are the same.

Why do we need fat?

Fat is a component of all your cell membranes and brain tissue, it helps the body to absorb fat-soluble vitamins (A, D, E and K) from food, provides energy, insulation and a thin layer of fat protects all your organs.

While fat is a vital nutrient, some fats are healthy but others are not and can, over time, cause a lot of harm.

The good fats

The good fats are all polyunsaturated – omega-3 and omega-6. Your body needs them for brain tissue to function and for cell growth, reproduction and maintenance. However, as your body cannot make them, they have to be supplied through diet.

Plants contain plenty – nuts, seeds and pulses are particularly good sources. It’s easy to get all the omega-6 fats you need from plants so, really, you need to focus on omega-3s. Rich sources are ground flaxseed, shelled hempseed, chia seeds and walnuts – and oils made from them but they should be used cold to preserve their nutritional value. Rapeseed oil is another great source and can be used for cooking.

Omega-3s from plants come in two forms – ALA (alpha-linolenic acid) which your body converts to EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). There’s an ongoing debate about the conversion rate and whether our bodies are effective enough to make all the EPA and DHA we need. Fish oils contain ready-made EPA and DHA which is why some people think they are better sources of omega-3s but fish don’t make these fats – they get them from consuming tiny algae (microalgae). If you want to go straight to the source, you can opt to take a supplement made from these algae that contains both EPA and DHA.

The bad guys

‘Bad guys’ may sound like an exaggeration but it’s not. There are two types of fat that we really don’t need and worse than that, they have been shown to directly contribute to disease if consumed regularly.

The first is saturated fats – fats that are solid at room temperature and come mostly from animal foods but also coconut and palm oil. We have no need to consume saturated fat because our bodies can make it. Diets high in saturated fat raise blood cholesterol levels and increase the risk of heart disease, stroke, obesity, type 2 diabetes and some types of cancer. If you’re a fan of coconut oil, use it very sparingly and try to avoid palm oil altogether.

The second, even worse, type is trans fats, also called hydrogenated fats. These also increase your risk of heart disease and stroke by raising cholesterol levels but to twice the effect of saturated fats! Many manufacturers have finally stopped using hydrogenated fats but you can still find them in some processed foods such as sweets, biscuits, pastry products and savoury snacks. They are made by an hydrogenation process which converts liquid vegetable oils into solid fats. The final product is called hydrogenated (or partially hydrogenated) vegetable oil/fat – another name for trans fats. They are to be avoided at all costs so always check the ingredients on processed foods.

The in between

Many plant-based foods and vegetable oils contain monounsaturated fats which are neither essential nor harmful. The main danger is that they can replace polyunsaturated fats in your diet if you’re not careful.

Probably the most common one is oleic acid – an omega-9 fat – the main oil component of olives, macadamia nuts, avocados, sunflower seeds and oils made from them. These are very popular foods and you don’t have to give them up but just make sure you also have good sources of omega-3s in your diet.

Is margarine good or bad for you?

Many people see margarine as the paramount unhealthy, processed food but while that was once true, it isn’t anymore. Margarine was first made of animal fats, then from hydrogenated/trans-fats and then, as their harmful effects became more widely known, most manufacturers changed their ingredients. Now, margarine doesn’t contain trans-fats anymore but check the ingredients to be certain. Even better, many types of margarine now have healthy, polyunsaturated fats added.

How much fat should you eat?

Fat is the most energy dense of all the macronutrients. It contains more than twice as many calories weight-for-weight as protein or carbohydrate. That’s why it’s a good source of energy but also why we don’t need too much of it.

It’s important, however, to ensure your daily omega-3 dose, which you can get from about a tablespoon of ground flaxseed or chia seeds. It’s best to soak your chia seeds first so they are more digestible but 20 minutes is all they need. If you choose walnuts, you’ll need a moderate handful or you can add a couple of tablespoons of hempseed to your smoothie or pasta dish.

When it comes to oils, a tablespoon per portion is more than enough – you certainly don’t need more. Choose rapeseed oil for cooking and virgin olive oil for cold foods – it doesn’t contain much of the essential fats but it’s full of antioxidants!

Some people avoid nuts and seeds because of their fat content but that’s a mistake. A small handful or two tablespoons daily is a healthy portion size that supplies important vitamins and minerals, protein, fibre and good fats.

What about fat-free diets?

Most foods naturally contain some fat so it’s technically impossible to have a completely fat-free diet but it usually means no added fats/oils and no nuts, seeds or avocados. For a healthy person, it’s not advisable but some research suggests that people with heart disease have greatly improved their health with a plant-based and almost fat-free diet. It can help to reduce cholesterol plaques in blood vessels and lower the risk of further complications. However, you should still make sure you have your daily dose of omega-3s.