This is where you will need to don your lab coats because beebleblog will now turn into a bit of a science lesson. Hopefully we will able to keep it more interesting than the science lessons we all remember (or not in some cases – Beeble).

There is a widely held belief that goes like this “When heating the oil when cooking you are in fact starting your own chemical experiment where unsaturated fat (good fat) becomes saturated (bad fat)”. If you are one of these people that are using oil in your cooking (olive or sunflower) you may be cooking away thinking you are being healthy by choosing olive oil, however this is not the case when heating is involved.

What are oils?

Quite simply oils are fats. Whilst fats are generally solid at room temperature oils are liquid. Fatty acids are part of the makeup of fats and oils and it is their structure that decides the flavours, textures and melting points. It is also the fatty acids that decide whether the fat or oil in question is a saturated or unsaturated fat or, in other words, good or bad fat.

What are Fatty Acids?

Fatty acids are simply a chain of carbon atoms all holding ‘hands’ and it is how they hold ‘hands’ that determines how the fat behaves. (Still with us or have we managed to send you to sleep yet? – Beeble).

What are Saturated Fats?

Saturated fats (bad fats) are usually solid at room temperature and in their natural form are normally from animal sources, e.g. butter and lard. The picture below shows the saturated fatty acid and you should notice that all the carbon links are indeed either linked to another carbon atom or a hydrogen atom. Each carbon atom has 4 ‘arms’ that need to be joined to another atom. In this case you can see that all the carbon atoms are joined to another atom and this is what saturated fat looks like, all the carbon atoms are saturated with another atom.

What are Unsaturated Fats?

Unlike saturated fats, unsaturated fats are usually liquid at room temperature and come primarily from vegetable oils and oily fish. The picture below shows the make up of a mono unsaturated fat and the immediate difference is that not all the carbon links are joined to a hydrogen atom. There are two carbon atoms that are linked to each other and these change the properties of the fat to a liquid at room temperature. Good examples of mono unsaturated fats are olive oil, rapeseed oil, peanut oil and avocado. This type of fat is much better for you than the saturated fats.

Polyunsaturated fat

Below is a diagram of another unsaturated fat’s molecular make up. This fat is known as polyunsaturated fat and the difference between this and the mono unsaturated fat is that there is more than just one carbon atom link not connected to a hydrogen atom. Good examples of polyunsaturated fats are sunflower oil and corn oil.

I hope we haven’t lost you yet because it is about to get interesting and to the point of this post.

Why can unsaturated fats (good fats) be bad for us?

Unsaturated fats can be “cis” fats or “trans fats”. “Cis” fats are natural and would be found in good quality cold pressed olive oil and unheated this oil can be very good for our bodies. “Trans” fats have been in the news a lot lately and were recently banned from cooking in a few selected areas in America. However this hydrogenated fat (forces those free carbon atoms in the unsaturated fat diagrams to hold ‘hands’ with hydrogen) is not only found in cooking at fast food restaurants but it is also found a little closer to home like in hydrogenated margarines.

The “cis” fat can be converted to a “trans” fat through a process called hydrogenation and also heating. It is this heating that should make you realise where I am going with this. When we think we are being healthier by choosing olive oil to cook with because of its health benefits, we are over looking the fact that the heating involved in cooking is actually changing this healthy fat to a trans fat which over time is detrimental to our health.

What is hydrogenation?

This is a process used by companies like margarine manufacturers to change liquid oils (good oils) to solid oils (bad oils) and requires a nickel catalyst (nickel is used to make the chemical change take place, but it does not appear in the end result). This means that the original unsaturated fat now becomes solid at room temperature and is now saturated and unhealthy for our bodies. The margarine companies found that partial hydrogenation allowed them to make their butter replacement easier to spread. Whilst it is not fully hydrogenated it is still a trans fat and very bad for our bodies.

What’s wrong with heating oils?

Trans fat can also occur when good fats are heated over a period of time and instead of using nickel as a catalyst it uses oxygen which all our homes have in plentiful supply. The heating of the oil starts a process called oxidation which has the same effect as partial hydrogenation and forces the carbon atoms that are joined to other carbon atoms to join with hydrogen atoms instead. This of course makes the oil become more saturated and therefore worse for our health.

What can you do?

The advice is easy: avoid frying foods as much as you can and instead grill your food which involves no extra oil or fat, or use a griddle pan which also requires no oil or fat. If you do need to use oil still use a good quality oil but don’t just pour it in like you were filling your car up; instead wipe the oil over the surface of the pan to prevent any sticking. The less you use the better!

You may have also noticed the mention of margarine and that it is made using the hydrogenation process which raises a whole new subject about how good margarine is for you. The advice though is similar; try not to use it and when you do please use it sparingly.

Like nearly all foods that are bad for you it often takes large quantities over long periods of time to cause health problems. The trick is to treat yourself to these foods and not make it a regular event. If you suffer from high blood pressure, are overweight and/or have high cholesterol then my advice would be: make a drastic change now and ban the bad oils, fats and other foods that are making your situation worse. The only way you will improve your health is to make the change now.

We wish everyone trying to make a change to their lifestyle all the best and success with their journeys.

Related posts

• The Health Benefits of Polyunsaturated Fats (0)
• The Health benefits of Monounsaturated Fats (9)
• Arnold Schwarzenegger is the Terminator of Trans Fats (2)

This entry was Posted on Tuesday, September 16th, 2008 at 4:16 pm and is filed under Diet. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.