There are certain buzz words when it comes to our dietary intake, some of these have become almost dirty words – especially in the media. One such word is “fat”. However, most fat is not at all bad- in fact, it’s good for us, even essential! That makes understanding them necessary.

Trans, unsaturated and saturated fats and their chemical structure.

Fat is sometimes split into “good” and “bad” fats. The good ones being polyunsaturated and monounsaturated fats, the bad being trans fats and saturated fats.

Trans fats are unsaturated fatty acids. Unsaturated means that there are carbon to carbon double bonds in the structure, which we can see highlighted by the blue ring. Now you may have heard of trans fats before and be surprised to learn that they’re unsaturated, because monounsaturated and polyunsaturated fats have such a good reputation for being good for us, but these fats have different chemical properties because of that double bond.

Trans fats are in the trans configuration whereas monounsaturated and polyunsaturated fats are in the cis configuration. Trans meaning “across,” cis meaning “on the same side” (in Latin) which is known as geometric isomerism. The trans configuration seems to make fats awful for us, whereas the cis configuration makes fats good for us.

Finally, we have saturated fats, which lack the double bond of the unsaturated fats. Meaning their carbon atoms are “saturated” by hydrogen atoms.

The Saturated fat myth

We’ve heard pretty much all our lives that saturated fats are bad, but this is emerging to be untrue. The idea that saturated fats are bad for us came from a study done in the 1960s called the seven countries study, which saw a link between high saturated fat intake, cholesterol and heart disease. Unfortunately, the man who wrote the study (Ancel Keys) ignored countries where Saturated fat intake was high, and heart disease was low. Metanalysis studies (studies that look at the results from many studies) are emerging to show saturated fat doesn’t cause heart disease. Take a look! Here and here.

Why is fat important?

Fats are essential in the body, but why? Well, they’re an excellent energy source and energy store; they provide essential fatty acids for our cells, nerves, and brain; they help to maintain healthy skin and tissues; they are important in transporting vitamins that dissolve in fat, and they are necessary for the formation of steroid hormones.

Essential fatty acids

The essential fatty acids; ALA, an omega 3 fatty acid and LA an omega 6 fatty acid; are polyunsaturated and must be provided in the diet because they cannot be made in the body. We should consume more omega 3s than 6s though most people do the opposite. Omega 3 consumption: is shown to reduce the risk of mortality from cardiovascular disease; is implicated in proper heart function and is essential for keeping joints healthy.

Fat as an energy source

The breakdown of fat in the body will yield 9 calories per gram, compared with 4 from protein or carbohydrate, that makes fat an excellent source of energy. In fact, fat is our body’s preferred source of energy, and our body will preferentially use fat as another source of energy.

The takeaway – Fat is something we need, not something to be feared. It’s essential in many body function. Dietary fats are either trans fats, unsaturated fats or saturated fats. Only trans fats are bad for us. Fat is a brilliant energy source and our body’s preferred source of energy.


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