NUTRITION
FATS
where saturated fat increases LDL cholesterol, mono-unsaturated fats increase high-density lipoprotein (HDL) cholesterol. This essentially hoovers up excess LDL cholesterol within the circulatory system, allowing it to function properly. This doesn’t mean it’s OK to consume lots of saturated fat and seek to mop this up with a high intake of mono-unsaturated fat – rather, we should aim for a healthy intake of total dietary fat. If you favour mono-unsaturated fats over their saturated counterparts, this will help keep the cardiovascular system healthy. In terms of fat as a fuel, many people do not realise that a fiſth of the energy we consume should come from fat, which equates to around 45g-50g per day for men and women respectively. Around two thirds of this should be mono-unsaturated fats.
POLY-UNSATURATED FATS Body fat is made up of fat cells that contain compounds called
triglycerides.These
are made up of a whole load of carbon atoms, which are bonded – or chained to – hydrogen molecules. At this level, saturated fat is so called because all of the carbon atoms that make it up are bonded to a hydrogen molecule, thus it is ‘saturated’ with hydrogen. One of the carbons in mono-unsaturated fats has a more complex double bond to the hydrogen, and in poly-unsaturated fats two or more of the many carbon molecules that make up the triglyceride are double bonded.
When the body breaks fat down to use as energy, cuting the single bonds is analogous to cuting the cord on a rope bridge, whereas breaking a double bond is rather like blowing up the Forth Road Bridge. Therefore, breaking the tough double bonds in poly- unsaturated fat can cause a bit of damage to the body’s cells. So, while beter then saturated fat, poly-unsaturated fat intake should be lower than mono-unsaturated where possible. It also seems that too much poly-unsaturated fat can lower HDL cholesterol, stopping its artery-clearing action. You should consume less of this than mono-unsaturated fats, but around 8% (or 20g) of poly-unsaturated fats is recommended.
OMEGA-3 AND OMEGA-6 OILS Sub-categories of poly-unsaturated fat are Omega 3 and Omega 6, and these have been a point of much interest to the nutritional community over recent years. O6 is generally found in plant oils while O3 is found in fish and fish oils, particularly, cold water fish, such as salmon and mackerel and also in some nuts and seeds, including flax and walnuts. Traditionally, in Asian or Mediterranean cultures, the intake of O3 and O6 is well balanced, but in western diets we tend to eat a lot more O6 than O3. What’s important here is something called an ‘inflammatory response’. Our bodies produce an inflammatory response when something alien is present. It works either by sealing it off – such as in injury – or by eliminating it altogether, as with infection. Dr Peter Atia, who recently gave a
webinar on swimming nutrition for Open Water Source (ows.openwaterswimming.
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FATS TO INCLUDE Type of Fat
Saturated Fat
Sources
Coconut, Coconut oil, Baked Goods, Buter, Lard, Cheese, Fried foods, Biscuits, Pastry and Take away meals (Processed foods may also be a source of Trans Fat)
Mono-Unsaturated Fat Sunflower Oil, Macadamia and Pecan Nuts, Avocado, Hazlenuts, Peanut Buter, Pork, Olives, Olive oil
Poly-Unsaturated Fat Omega-6 Vegetable Oils
Omega-3 Oily fish (Mackerel, Salmon, Fresh Tuna, Herring), Olive oil, Olives, Sweet potato, Cod liver oil, Flaxseed oil, Walnuts, Almonds
com) described inflammation in the body as being like a fire in one’s house: “It’s great having a litle bit that’s controlled to keep you warm but out of control, it will burn your house down.” This has a direct application for swimmers. Hard training sets leave
you aching, as the body protects and heals stressed muscle tissue, which is a positive thing. However, by consuming a diet high in O6 and low in O3 the inflammatory response is heightened, causing an increase in discomfort and recovery times. As well as reducing the inflammatory response, evidence shows O3 consumption can help develop strength and endurance by improving the quality of red blood cells. It is also said to prevent these cells clumping together, so permiting higher oxygen-uptake. This has a significant impact on training effectiveness and recovery time – crucial factors for any swimmer working towards performance goals.
TRANS FATS While trans fats occur in a limited form in some meat and dairy products, they mostly enter our diet through a process called hydrogenation – which is why it’s not mentioned on food labels. Companies use hydrogenation to turn oily lipids into solid, spreadable fats, via heat treatment. This process, which also occurs during frying, turns good fats into bad ones. This has led the Food Standards Authority to declare that trans fats not only have litle or no nutritional benefits, but that the effects of trans fats may be worse than saturated fats. My advice, then, is stay away from foods – usually processed – that contain hydrogenated or partly hydrogenated oils.
TAKE HOME MESSAGE Open water swimming is about geting out in the fresh air and pushing oneself, so it makes sense for our diet to echo these goals. If you haven’t already, try to reduce the amount of saturated and trans fats that you include in your diet. Make sure the fats you do eat come largely from mono-unsaturated fats, while ensuring you take in enough Omega-3, and use good quality olive oil for cooking, as it is a source of all the good fats. Lastly, use nutrition labels to help you decide what to buy, and remember that only a fiſth of the energy in your diet should be drawn from fat. ○
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