Good Fats & Bad Fats : Do You Know Which is Which?
When I trained as a nutritional therapist in the noughties, we were taught that the bad fats are saturated fat and trans-fats, while the good ones are the essential fats: omega-3 and omega-6. It almost didn’t matter why a client would come to see us – the recommendation was always to reduce saturated fats, avoid trans-fats and increase essential fats.
Since then, that recommendation has completely changed. It turns out, that saturated fat has been vilified unfairly, while at least one of the essential fats – omega-6 – has been overrated. Why?
I am sure you are aware that nutrition advice can be very confusing, as recommendations frequently seem to do a U-turn, as in the case of fats. One reason is that nutrition is actually very complex, and jumping to the most obvious conclusion – for example that cholesterol in our food becomes cholesterol that clogs up our arteries – gets proven wrong and too simplistic time and time again. The more we learn, the more we realise we don’t know.
Another reason for the confusion in nutrition is the fact that it is quite difficult to study: We can never completely control people’s diets and other lifestyle factors, let alone for a meaningful length of time, as unlike lab rats, they are free to do their own thing. In trials, groups of volunteers are assigned are certain diet – in a well-funded trial (which are scarce in nutrition as there is not much money to be made with food) food may even be supplied to the subjects to improve compliance, but at the end of the day researchers will never know whether participants stick to the diet 100%, particularly if it is one that is difficult to endure. They are often not conducted for long enough to give a reliable picture of the effect of the tested diet.
In the case of fats, however, other, very powerful and probably unexpected factors affected what we were taught about which fats are good and which fats are bad, and those are politics, business and to some extent corruption. It is quite a fascinating story, and if you would like to learn more, I can recommend Tina Teichholz’s book “The Big Fat Surprise” for the full story.
First of all: all natural fats are generally good fats. We now know that dietary fat is not what makes us fat, it’s sugar and insulin that do that. For more details click here.
Saturated fats are those that are solid at room temperature, such as lard, tallow, butter, ghee, and coconut oil. It has been thoroughly vindicated and in fact has never actually been proven to cause heart disease.
Monounsaturated fats are the predominant fat in olives, avocados and almonds. They have always been classified as ‘neutral’, so were never thought to be damaging. These oils are more stable than essential fats and can take a certain amount of heat, though not as much as saturated fats.
Omega-3 fats are one of the two groups of essential fats. ‘Essential’ in nutrition is used for substances the body cannot make, but that we have to consume with our food. All essential fats are ‘polyunsaturated’ fatty acids, which makes them vulnerable to heat and light. They go rancid more easily than saturated or trans-fats. Omega-3 fats can convert into hormone-like substances that have anti-inflammatory properties. They are found in seaweed (very small amounts), walnuts, pumpkin seeds, milled flaxseeds, chia seeds, and predominantly in oily fish, but also in the meat and dairy of grass-fed cattle or in game. If you are using omega-3 oils in the kitchen (e. g. walnut oil, flaxseed oil), you should buy them in opaque (glass) bottles, keep them in a dark cupboard, even the fridge, and never heat them.
Trans-fats are artificial fats. They are derived from plant oils that have been chemically hardened – similar to saturated fats, but with completely different properties. They were a godsend for the food industry, as they are cheap and durable, perfect for the creation of processed foods with a long shelf life. Trans-fats also form as a result of high-temperature frying – deep-frying. They are now considered carcinogenic and pro-inflammatory. You would find them in margarine, deep-fried foods such as crisps, fried chicken and other junk foods as well as most baked goods. Trans-fats are best avoided, they have no redeeming features and are very damaging.
Omega-6 oils are actually ‘essential’, just like omega-3, so we do have to eat them. The problem is that we are having too much omega-6. Like omega-3, these oils can convert into anti-inflammatory compounds, but unlike omega-3, there is a second option: the can become pro-inflammatory as well. The ratio between those two should be 1:1 to 4:1 at most, but the Western diet tends to provide much, much higher levels of omega-6 than omega-3, so that the ratio can be as high as 20:1 and even 30:1.
Omega-6 fatty acids are the predominant fats in grains and pulses such as soy, and our main sources are, perhaps surprisingly, not plant oils that we consume directly, but indirectly through factory-farmed meat – where cattle is fed on grains and soy – and processed foods. Moreover, the saturated-fat scare that we’ve been exposed to over the last 50 years has meant that more and more people turned to margarine as a replacement for butter – another source of omega-6 (and of course trans-fats).
Don’t be afraid of fats. Fat is not the enemy, but make sure that it comes from real food sources such as nuts, seeds, olives, avocados, grass-fed beef and its dairy, game, and fish.
Avoid processed foods, junk food, deep-fried foods, cheap supermarket cooking oils that come in clear plastic bottles, and margarine. Don’t cook with polyunsaturated oils such as sunflower, flax or walnut oil. Olive oil, avocado oil and groundnut oil are more stable, and the saturated (solid) fats can take the highest temperatures.