Not all dietary fats are evil
Despite what we are lead to believe, fat in our diets is not a huge danger to our lives. Perhaps surprisingly, it should make up 15 to 20% of our diets.
Any food-type in excess will cause undesired health problems, and fat is no exception. It has more than double the amount of calories per gram than carbohydrate and protein, and therefore excesses of fat will lead to a faster gain of body fat than excesses of either carbohydrate or protein. Excess body fat is inherently damaging to our health and is closely linked to the development of disease, including coronary heart disease, diabetes and cancer.
Fat does have some very useful purposes, including:
- Delaying release of food into the body (remember that feeling of being hungry all the time during a low-fat diet?). Fat actually slows down the entry of food into the body, meaning you stay fuller for longer and therefore end up consuming less
- Protection of the covering of your nerves
- Formation of the walls of almost all the body’s’ cells, and maintenance of their structures
- Formation of most of the central nervous system (brain and spinal cord)
- Protection of internal organs
- Enhancement of liver function
- Utilisation of certain vitamins
- Insulation!
Unfortunately, none of the above are a reason to celebrate with huge bar of chocolate, the type of fat you eat is crucial.
3 types of fat
There are three types of fat, although, in reality; they are all a combination of each other in varying amounts. This is why we are able to survive without any saturated fat.
The three types of fat are:
- Saturated fat
- Monounsaturated fat
- Polyunsaturated fat
Saturated Fat
This is the type of fat that we should take care not to consume to excess as the body more readily stores it. Common sources include dairy products, eggs, poultry and meat. Non-animal sources include palm oil and coconut oil.
Interestingly, an increasing number of researchers have failed to find a correlation between saturated fat intake and the development of clogged arteries (Ravnskov, 1998). Evaluation of the fat found within artery walls as a result of Coronary Heart Disease showed that only 26% is saturated fat (Felton, 1994)
Monounsaturated Fat
Diets high in monounsaturated fats have been shown to lower both LDL cholesterol and plasma triglycerides, and are therefore thought to reduce the risk of coronary heart disease (Kris-Etherton et al, 1999)
Common Sources include olives, olive-oil, avocados, nuts and seeds.
Polyunsaturated Fat
More commonly known as essential fatty acids, polyunsaturated fats are sub pided into Omega 3 fatty acids and Omega 6 fatty acids. As the popular name suggests, these fatty acids are essential to the diet as the human body is unable to create them itself. There is a further polyunsaturated fat – omega 9, but this is not an essential fat as it is not obtainable through the diet; rather, it is made by the body.
Sources of omega 3 include oily fish (salmon, fresh tuna steaks, mackerel etc), linseeds and hemp seeds. I like to put a tablespoon mix of seeds on my cereal in the morning, and I try to eat at least 3 portions of oily fish a week. Omega 3 has been a huge buzzword for the media lately and as a result we can now buy, amongst other things, bread and milk fortified with omega 3.
Sources of omega 6 include sunflower seeds / oil, pumpkin seeds and walnuts.
Ideally, your diet should contain an equal balance between omega 3 and omega 6, but our diets today have a balance of more like 1:16!! This could be because lots of junk / convenience foods contain high levels of sunflower oil, which as mentioned above, is a rich source. Excessive amounts of omega 6 have been shown to promote development of cardiovascular disease and cancer, as well as inflammatory and autoimmune diseases (Simopoulos, 2002).
When present in the body, Omega 3 and Omega 6 essential fats allow the creation of hormone like substances called prostaglandins, which regulate metabolism within the cells. Metabolism is the speed at which the body uses energy, the quicker it does this, the less likely it is to store fat.
The functions of the first type of prostaglandins, formed in the presence of omega 6, are:
- Thinning your blood
- Lowering blood pressure
- Decreasing inflammation and pain
- Improving immune system function
- Balancing blood glucose levels
Signs of deficiency include:
- Eczema
- Dry eyes
- Excessive thirst
The second type of prostaglandins, formed in the presence of omega 3, help with the following:
- Vision
- Learning ability
- Co-ordination
- Controlling blood cholesterol
Signs of deficiency include:
- Dry skin
- Tingling in arms and legs
- Poor memory
Trans-fats
As the name suggests, trans-fats are fats that have been turned from one type into another, for example when sunflower oil is turned into margarine via a process that heats the fat excessively. This is the dangerous fat that must be avoided like the plague as it is unstable, unnatural and the body cannot deal with. It prevents the metabolism of good fats, and are increasingly associated with a variety of diseases, including coronary heart disease. Trans-fats have also been noted to increase LDL (“bad”) cholesterol levels.
A study carried out in 1994 by Willett and Ascherio estimated approximately 30,000 premature coronary heart disease deaths a year could be attributed to the consumption of trans-fatty acids.
Common sources of trans-fats include many margarines, biscuits, cakes, take-away foods, pies, pasties, pre-prepared foods, many “low-fat” foods.
Fat - Conclusion
I hope this article has increased your awareness of where fat should fit into your diet, and why you should not pursue the highly promoted low fat diet.
Please do visit the reference section of my website to download free reference articles to help you make the best nutrition and fitness choices you can.
Courtesy of Heather Gillam
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