For many years now we have been encouraged to eliminate fat from our diets. Food manufacturers have jumped on the bandwagon and produce huge amounts of low fat and fat free products. But since people started pursuing a low fat diet the levels of obesity have risen exponentially. Low fat products always have a high sugar content and its largely sugar that makes you fat rather than fat.
By reducing fat in your diet you are denying yourself at soluble nutrients such as A, E, D and K and are more likely to damage your health than improve it.
It is not my intention here to make you an expert on fat. I just want to give you a broad overview so you are better placed to make useful choices when it comes to what fats to include and what to avoid in your diet.
The Importance of Fats (Lipids)Lipids may well be a less familiar term to you than fats. But it is a broader technical term that refers to both solid fats and liquid oils as well as more complex lipids such as cholesterol and phospholipids.
The function of lipids in your body are quite broad and include:
- providing a source of energy
- provide the building blocks for the outer layer of each cell in your body
- regulating hormones and co-enzyme functions
Types of Lipids
Saturated Fats:Saturated fats are simple fatty acids. They have been cast as the undisputed baddies of fats. The fat molecules however are chemically stable under high heat which means they do not react with oxygen creating free radicals. Sources of saturated fat include most animal fats, lard, butter, coconut butter, and palm fat. These are all traditional cooking fats owing to that stability under high heat.
Saturated fats can be created in the body as well as coming from foods. They are important for cell membrane structures, production of bile salts, immune functions, cellular signalling and important for your lungs.
Monounsaturated Fats:Monounsaturated fats (MUFAs) are also simple fatty acids. They are unsaturated but only in one place in their molecular structure. Monounsaturated fats are liquid at room temperature. Butter is, for example, mostly saturated fatty acids and is solid at room temperature, olive oil on the other hand is mostly MUFAs and is liquid at room temperature. MUFAs are less stable than saturated fats in high heat. They are therefore suitable for medium temperature cooking such as sauteing or baking. Food sources include olives and olive oil, avocados, peanut and soybean oil.
Polyunsaturated Fats (PUFAs)Again simple fatty acids, PUFAs are less stable in heat. The react easily with oxygen creating free radicals. PUFAs are so unstable that they are not suitable for cooking at all. Food sources include all seed oils such as sunflower oil, safflower oil, linseed (flax seed) oil, hemp oil, walnut oil, free-range egg yolks, cold water fatty fish such as mackerel, salmon, sardines and herring and cod liver oil.
PUFAs and Free Radical DamageFor many years now we have been told that PUFAs and good for us and we should eat more of them. As a result people switched from butter to margarine and started using vegetable oil to cook instead of lard or butter. But this advice may not be useful or accurate.
PUFAs can be very beneficial for our health. Included in this category are the essential fatty acids (EFAs). EFAs break down into two categories: omega 3 fatty acids and omega 6 fatty acids (more about these later). Our bodies cannot make essential fatty acids, we have to get them from food. EFAs are however very fragile. When they are exposed to oxygen, light and heat they go from being health givers to producing damaging free radicals (more on free radicals in later posts - in brief free radicals are known to cause damage to blood vessels leading to hardening of the arteries).
So how do we get the health benefits without the free radical damage? The answer is in the whole foods where they are always protected from light and oxygen and combined with antioxidants (such as vitamins C and E). Vitamin E for example is present in nuts and seeds which is where we get most of our PUFAs. Antioxidants neutralise free radicals. Industrial food production ignores the wisdom of natures. When foods are commercially processed the oils are damaged and the antioxidants are left behind. Some manufacturers have however now started to produce cold pressed oils from seeds which causes minimal damage to the oil and removes the free radical menace.
Essential Fatty Acids (EFAs)EFAs include Omega 3 and Omega 6 fatty acids. There are various forms of Omega 3 fatty acids such as Alpha-linolenic acid which comes from seeds such as linseed, eicosapentaenoic acid (EPA) from marine algae and fish oils and docosahexaneoic acid (DHA) which is also from fish oils. Omega 6 fatty acids also come in different forms. Linoleic acid from nuts and seeds and arachidonioc acid from animal fats such as egg yolks, dairy fat and meat.
The functions of EFAs are very complex. EFAs are essential to the production of chemicals in our bodies which govern:
- vascular (vascular means in relation to blood vessels) dilation and constriction
- blood clotting and thinning
- inflammatory and anti-inflammatory response
- respiration, mucous production
- blood pressure control
- water retention and water excretion
Many people's diets have become very unbalanced in terms of their EFA intake. In general Omega 6 are more prevalent in most peoples diets and many people consume no Omega 3 at all. Essential fatty acids are just that, essential so given the imbalance its no wonder so many people are suffering with poor health.
So Which Fats Do We Need and Which Should We EliminateEssential: We all need essential fatty acids. Omega 3 and Omega 6 must be in balance for optimal health. We need more Omega 3 than Omega 6. Nobody in our society is short of Omega 6 whilst almost everyone is short of Omega 3 which explains why our society is experiencing such a rise in degenerative conditions such as heart disease, arthritis, diabetes, high blood pressure etc. Because they are unstable and easily damaged they are best consumed from whole food sources, cold pressed oil or high quality supplements (that are free of mercury contamination).
Healthy: These fats have benefits for our health but are not essential. Extra Virgin Coconut Oil is mostly saturated however it provides energy and is quickly and easily absorbed without the need for bile salts. Good for people who have difficulty absorbing fats and oils. Naturally anti-fungal (so great in the fight against candida and yeasty infections) and they help to stimulate the immune system. Suitable for high temperature cooking and for people with a fatty liver.
Butter has a similar molecular structure and also provides vitamins A and E. People who are sensitive to dairy can often tolerate butter, but more often ghee.
Monounsaturates like sesame oil and olive oil have long been associated with good health. In addition olive oil contains phytonutrients that act as anti-oxidants. Monunsaturated oils have long been associated with lowering the bad cholesterol. Suitable for medium temperature cooking.
Neutral: Most other fats and oils even including lard, poultry skin and cream can be healthy in moderation. Lard and poultry skin contain vitamin D. So as part of a diet including wholegrains, pulses, vegetables and fruit these fats will do you no harm in moderation (although I know it goes against what you have been told for years).
Fats That Will Harm Your Health: The only fats that are really damaging to your health are those that are manufactured by chemical companies. Synthesised or overly processed these fats give us nothing that we need.
Trans-fats are the result of hydrogenation (means to treat with hydrogen) of vegetable oils to make them solid at room temperature. You will find trans-fats in margarine, vegetable shortening, biscuits, and virtually all packaged foods under the name hydrogenated vegetable oil. Most fast foods are packed with them. Avoid these fats completely. There are some schools of thought that believe that once these kinds of fats are deposited in your body they cannot be removed because your body does not recognise what they are and has no way to deal with them. Likely to raise blood cholesterol levels, give you a fatty liver, raised blood pressure, make you fat, more prone to degenerative dieases, heart disease, age prematurely and rob you of your health.
Rancid vegetable oil is another really harmful oil. I recommend avoiding all "vegetable oil". Usually packed in flimsy, clear plastic bottles and hanging around on the supermarket shelf for months (not to mention how long they may be in your kitchen) these fragile polyunsaturated oils from sunflower, safflower and corn are no match for the high-temperature, high pressure and solvents that are used to extract them. The processing of these oils creates dangerous free radicals which can cause damage to our bodies and the other health issues listed for trans fats. Only buy polyunsaturates if they are labelled "cold expeller pressed" are sold in dark glass bottles and preferably stored in a refrigerator (which you should do at home too).
CholesterolCholesterol is a complex lipid. It is similar to simple fatty acids in that it can be unstable at high heat and react with oxygen to form free radicals. Naturally occurring cholesterol in egg yolks is health promoting (many studies have proved - and as early as 1972 - that there is no link between egg consumption and unhealthy levels of cholesterol in your body) whilst the cholesterol in powdered milk, powdered eggs and processed foods can be very damaging to your health.
Cholesterol is another fat that has been cast as a bad guy. Cholesterol is made in the body as well as being found in foods such as eggs, meat and fish. It is used in the body in cell membranes, bile salts and the myelin sheaths which protect nerves. Cholesterol is used to make vitamin D, the steroid hormones including oestrogen, progesterone, testosterone, cortisol, DHEA and aldosterone. Cholesterol is vital for good health. Many laboratory experiments which linked cholesterol with hardening of the arteries and heart disease used a very poor source of the lipid: powdered cholesterol. Whole food sources of cholesterol do not affect the blood cholesterol levels of healthy individuals. Cholesterol deprivation is much more harmful. 75% of people who have heart attacks do not have high cholesterol levels.
PhospholipidsPhosopholipids are complex lipids. They are the main component of the membrane on the outside of each and every cell. The cell membranes are semi permeable and create two interdependent but separate "oceans": one which exists inside the cell and the other outside. One of the most important food sources of phospholipids is lecithin which can be found in egg yolks. Phospholipids are also important for intercellular signalling, formation of bile salts, the formation of the neurotransmitter acetylcholine and the myelin sheath of nerve cells.
Broad OverviewSo I hope that has given you a little more information on fats and their importance in our diet. Don't be afraid of fat. I always tell clients my own personal rule of thum for deciding whats good for us and what's not: if we have eaten something for the last 50,000 years or so that we know of then continue to eat it, if we have only been consuming it for the last 50 years or so then your health will be better if you give it a miss. Butter and margarine are a great example of this rule.
In my next post I am going to have a look at Essential Fatty Acid Supplements before we move on to looking at what constitutes a healthy diet. Your feedback is welcomed.