First I feel it’s important to understand a little about the classification of fats. Some of you will may not be familiar with this topic but I’ll keep it simple and straight forward.
Very quickly, the difference really between oil and fat is simply that when we refer to an oil we are talking about a liquid lipid (a lipid is the technical name for fat). When we refer to a fat we are talking about a solid lipid. Generally, saturated fats are solid at room temperature and unsaturated oils are liquid at room temperature.
Dietary fats can be classified into 2 major groups:
The unsaturated fats are then further broken into:
- Monounsaturated (including omega 9’s)
- Polyunsaturated (including omega 3’s and 6’s)
- Trans-fat (both man-made and naturally occurring)
Figure 1 is a diagram of the fatty acid molecules (a fatty acid is what a fat is broken down into through the digestion process).
Figure 1: The chemical structure of saturate and unsaturated fats
Figure 2: Cis and trans configuration of linoleic acid (polyunsaturated fatty acid)
Saturated fat is completely saturated by hydrogen atoms, hence the name. It also contains single bonds in the fatty acid chain, unlike monounsaturated and polyunsaturated fats which contain double bonds. In figure 1, the unsaturated fats have arrows pointing to the double bonds (that saturated fats do not contain). Monounsaturated fats have one double bond (hence mono) and polyunsaturated have more than one (hence poly). With increasing number of double bonds, comes a lower smoking (the smoking point is the temperature at which the fat may sustain nutritional degradation), lower melting point and higher reactivity. Therefore by this reasoning alone, the best fat for cooking would be saturated and the worst would be polyunsaturated.
Ok, so I mentioned something about unsaturated fats having a higher reactivity than saturated fats. What exactly does this mean? Well, because a saturated fat is completely saturated by hydrogen, it makes it very stable and less likely to react with oxygen. This reaction with oxygen is called oxidation and it is what we mean when we say something organic has gone off. When a molecular chain is complete or if it does not have any exposed sections – such as where the arrows are indicating in Figure 1, it makes this molecular chain less likely to interact with other molecules (such as oxygen which is very reactive – just think about rust as an example). Polyunsaturated oils are the least stable and oxidise quite easily as they have the most exposed or reactive sections. As an example, you can leave butter (which is primarily a saturated fat) on your bench top for weeks without any reaction. I had my butter out during a heatwave and the only thing that happened was that it melted. If I was to do the same with polyunsaturated oil (like what we find in margarine) it will go off very quickly.
At the start I also mentioned a group of fats called trans-fats. Trans-fats are unsaturated fats that are in particular arrangement called a trans arrangement (the other type of arrangement is called cis which is the natural arrangement for a polyunsaturated fat – see Figure 2). The trans arrangement occurs when the fat is put through a process called hydrogenation (this can be partial or complete). Hydrogenation is basically where hydrogen atoms are fired at an unsaturated fat causing it to become partially or completely saturated. With a trans-fat, the unsaturated oil goes through partial hydrogenation which means only some of the carbons end up with hydrogen attached to them. Hydrogenation causes the oil to change shape and straighten out and puts the hydrogen on the opposite side of the carbon double bond. Figure 3 shows the process of hydrogenation and how the molecular chain alters in its arrangement.
Figure 3: Chemical hydrogenation of a polyunsaturated fat
With a trans-fat, the hydrogenation process causes the oil to solidify (or semi-solidify). The more carbons that have hydrogen attached to them, the more dense the oil becomes until it eventually solidifies (hence why a saturated fat is generally solid at room temperature). The major concern though, is that these types of trans-fats are not naturally occurring. There are natural trans fats which are NOT bad for us at all and in fact have been linked to decreasing CVD and cancer risk (wonder of all wonders). Naturally occurring trans-fats occur in ruminant animals and dairy products. An example of a naturally occurring trans-fat is conjugated linoleic acic (CLA). This fatty acid has been studied extensively has been shown to improve cholesterol profile and body composition, improve glucose control and has anti-carcinogenic and anti-atherogenic properties (Nicolosi, Rogers, Kritchevsky, Scimeca, & Huth, 1997). Man-made trans-fats though are a whole other kettle of fish. These fats have been strongly linked to a number of devastating diseases but none more so than Australia’s biggest killer; cardiovascular disease (Mozaffarian, Katan, Ascherio, Stampfer & Willet, 2006). The problem with the trans-fats is the alteration from the cis arrangement into the trans arrangement. This chemical process produces an unnatural end product which ultimately causes disruption at a cellular level leading to inflammation and a whole range of degenerative diseases and disorders. So I’m sure you’re asking why manufacturers would produce something like this? Well I’ll explain in more detail in part 2, but basically trans-fats are very cheap to manufacture and have an incredibly long shelf life. That is cause for concern in itself don’t you think? When even bacteria refuse to eat something (or simply can’t), it’s time to realise that this is not organic, it is not a food and we should not be consuming it either.
Ok, we’re nearly there but just a little more science before we move on. Fats are not simply classified as saturated and unsaturated. They’re also categorised by their molecular length which is of VITAL importance. A fat can be a long chain fatty acid (LCFA), medium chain fatty acid (MCFA) or short chain fatty acid (SCFA). Sometimes they’re referred to as short, medium and long chain triglycerides (SCT, MCT, LCT). Mann and Truswell state that “triacylglycerols make up about 95% of dietary lipids. A triacylglycerol molecule is formed from a molecule of glyercol (a three-carbon alcohol) with three fatty acids attached” (2012, p50). A triacylglycerol is another name for a triglyceride, just to add to the confusion. So what this means is that fatty acids are a part of a triglyceride molecule. Anyway, most saturated fats are short and medium fatty acids and are incredibly important for the body. We use them easily due to their length and have been shown to assist in weight loss. I beg your pardon I hear you saying!! Well, yes, it is true. The dirty little secret of the weight loss industry is that eating the right fats actually promotes weight LOSS and NOT weight gain. Wow! The only issue is, the weight loss industry likes to throw around the term ‘good fats’ and by that, they mean polyunsaturated and monounsaturated. This is a flat out lie as mono and poly fats are almost never medium or short chain fatty acids. They are generally long chain or very long chain. What this means is that the body has to chop up the fats first before they can be used. This tends to lend towards fat deposition rather than fat utilisation. So what am I getting at here? Short and medium chain fatty acids, as found in most SATURATED fats, are actually good for us and help us with weight loss. In fact saturated fats have many many health benefits including improving cholesterol profile, reducing visceral fat, improving physical endurance, assisting with appetite control, preventing atherosclerosis (build-up of plaque in our arteries) and improving immune function. Almost unbelievable right? Well I part 2 I’ll explain how we came to be so deceived on this topic.
Something else to ponder for a moment is that saturated fat is a naturally occurring fat found in the human body. What? Yes! It is true. Our body has a large amount of saturated AND unsaturated fat in it. In fact, we need saturated fat for every single cellular membrane in our body. Our membranes keep everything that is supposed to be in our cells, in; and keeps everything that is meant to be out, out. It is estimated that there are over 100 trillion cells in our body (that is 10 with 14 zeros after it or 100 000 000 000 000) and with each one of these needing saturated fats, the thought to exclude these out of our diets is completely preposterous. So I’m sure you’re wondering what good sources of saturated fat are; well one of the best is coconut oil. Coconut oil is incredibly high in saturated fat; most of which is lauric acid, a medium chain fatty acid. The health benefits of coconut oil is an essay in itself so just go and do yourself a favour and purchase some extra virgin organic coconut oil and start using it every day.
I realise there’s a LOT of information here so I have summarised it for you:
Saturated fat has/is:
|Characteristic:||What this means:|
|Low Reactivity||it will not go off easily|
|High smoking point||high temperatures will not affect it making it great for cooking and deep frying|
|Generally SCT or MCT||this is perfect for our body and easily used in cellular processes (particularly good for weight loss)|
|Naturally occurring||little ‘man’ interference in its production which makes it good for us|
|Found in the human body||We need it for every day processes such as cellular signalling (our nervous system), absorption of vitamins A, E, D and K, our skin, our hair, our cellular membranes, energy, temperature regulation and so much more!|
|Many health benefits||Our cholesterol profile improves, our immune function is supported, our brain and nervous system works better, our waist line improves, our bone density gets better etc.|
So what are some good sources of saturated fat? Well it’s hard to go past coconut oil so I’d start there. Other great sources include:
- Meat (preferably grass-fed)
- Chicken (preferably organic)
- Dairy (preferably grass-fed)
- Eggs (preferably free range)
- Butter (not margarine)
- Palm oil (sustainably produced)
With animal products I believe we should buy organic/grass-fed where possible and avoid factory farming. Factory farming is incredibly cruel and produces a poor quality product. Wherever possible, organic is the better option (for both meat and non-meat options) and even though it is expensive, you’re getting a better product.
Finally, some food for thought (pardon the pun).The above list is basically everything we’ve been told to stop eating because it makes us unhealthy and will kill us. However, if you take a look at health trends since we’ve been ‘fed’ this information, we’ve been getting more sick, we’ve become steadily more fat, we’re dying from lifestyle disease and the incidence and prevalence of new diseases are on the rise. A little perplexing don’t you think? I think so, seen as though people have wholeheartedly taken on the low fat and high carbohydrate message. So much so that fat is quite simply the pariah of society and the nutrition world. So, in Part 2, I will explain why saturated fat was demonised and how it has been to the detriment of our health that this vital fat was excluded from our diet. I’ll also explain why the advice we’re being given is all wrong and the devastating consequences it is having on our waist lines and our lives.
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