Which fats to cook with?

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There are a ton of different cooking oils and fats, here I look into why we need fats in our diet and which are 'healthy' to eat!

What is a Fat and why do we need it?

Fats are made up of a single carbon backbone with three fatty acid chains attached and so can be called 'triglycerides'. The fatty acids are produced when the fats are broken down, and it is these that our body needs for many functions including transportation of vitamins and upholding a strong nervous system. Although we want to break the fat down, we don't want to change the fatty acid structure too much as this leads to fat storage and fatty deposits in our arteries.

Triglycerides are transported in our bloodstream and they can be placed into three categories, Saturated, Unsaturated and Trans fats. They can be solid at room temperature being referred to as 'fat' or liquid as an 'oil'.

Saturated Fat

Saturated Fat, contrary to traditional belief is a healthy and vital part of a nutritionally balanced diet. It is solid at room temperature as the chain of carbon atoms on the fatty acids are straight and harder to lose its chemical structure. This makes it ideal for cooking with at high temperatures, especially frying as they do not get broken down in the cooking process. Because they have a straighter chain to their structure they are less likely to be stored in the body as fat. Saturated fats can also be found in whole milk, cheese and yogurt.

Examples of saturated fats for use in cooking are: Coconut oil, Palm and Kernel oil, Ghee.

Unsaturated Fat

There are two types, Monounsaturated Fats (MUFAs) and Polyunsaturated Fats which are both liquid at room temperature.

Monounsaturated means there is one kink or bend in the fatty acid chain where as Polyunsaturated means many kinks. Because of the more unstable structure of these fats they are better used at low temperatures or in salad dressings - this ensures their chemical bonds are not broken down and so hold more antioxidants and vitamins. MUFAs are great at lowering overall cholesterol and also decrease the risk of heart disease when used moderately. Polyunsaturated Fats typically have Omega3s and Omega6s which are called 'Essential Fatty acids', as our body cannot produce them itself.

Examples of MUFAs - Olive oil, avocado oil, chicken or beef fats.

Examples of Polyunsaturated Fats - Oily fish, corn and soya bean oil, Flaxseed.

Trans Fats

These are the bad fats people talk about. They are also referred to as Hydrogenated or emulsified because of the way they are produced. Hydrogenation is the process where liquid fats are chemically changed to solid fats so they last for longer at room temperature. Because of the chemical change, they contribute to raising Low-density Lipoprotein (LDL) which is also called our 'bad' cholesterol levels. The higher LDL levels cause a build up of arterial plaque clogging up our arteries. In turn this increases the risk of heart disease and also Type 2 diabetes.

For this reason, since 2006 manufacturers have to include all ingredients of Trans fats on their labels by law.

Examples of Trans Fats: Margarine, Pre-made biscuits and cakes.

In Summary:

Although Saturated Fat is believed to increase Cholesterol, more and more recent research points towards favouring saturated fat, especially for cooking in small amounts.

Use Saturated fats for cooking at high temperatures and Unsaturated fats for low temperatures and salad dressings. Remember, the more you change the chemical structure of the fatty acids, the more likely they are to get stuck as arterial plaque, stored as body fat, and lose their nutritional value;

this is why it is not only the type of fats you consume, but also how you prepare them and heat them!

Trans fats were invented because of research over 50 years ago, most of which shows that fats raise cholesterol and have a limited shelf life. However, all fats can raise overall cholesterol if consumed in too great a quantity, and used incorrectly. Trans fats unfortunately have been linked to more health problems in modern studies than any other kind.

" The science showing that trans fats increase LDL cholesterol levels is outstanding and very strong. " Alice H. Lichtenstein, D.Sc. professor of nutrition at Tufts University, on the topic of hydrogenation.

Wise words from the Tufts professor supporting the modern view about trans fat health risks.

Here are some great links to check out on Saturated and Unsaturated fats:

http://www.mayoclinic.org/healthy-living/nutrition-and-healthy-eating/in-depth/fat/art-20045550

http://www.hsph.harvard.edu/nutritionsource/fats-full-story/

The Harvard article is a particularly good read.

Best,

Dejan.

antioxidants cholesterol coconut oil Fat fatty acids harvard hydrogenated fat omega 3s omega 6s saturated fat unsaturated fat

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