Tuesday, June 9, 2009
Nutrition: Fatty friends
Many of us suffer with fat phobia, and in a misguided attempt to boost our ﬁtness, lose weight or keep healthy we are depriving our bodies of healthy, and sometimes essential, fats.
Fat isn’t bad, in fact it’s essential to everyday life functions. Fat helps us absorb vitamins (especially A,D,E and K), gives us energy, provides insulation, regulates hormones, metabolism and aids digestion.
But not all fats are created equal. Current recommendations are to limit our intake of saturated fats (found in meat, dairy and reﬁned oil such as palm oil) and avoid trans fats – which are linked to health conditions such as cardiovascular disease – altogether. Monounsaturated fats found in olive oil, many nuts and avocados are considered healthier fats.
The essential fatty acids (EFAs) – known as Omega 3 and 6 oils – are probably the most important group. EFAs cannot be made in the body and have to be consumed in the diet.
Omega 3s known as alpha linolenic acid can be converted by the body into EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) which are particularly important for health. Unfortunately this conversion process can be inefﬁcient so it is preferable to eat foods naturally rich in these active fats, primarily oily ﬁsh (see below).
The Omega 6 known as linoleic acid is converted by the body into active gamma-linolenic acid (GLA), which is commonly found in evening primrose oil and borage oil.
Another Omega 6 fat, arachidonic acid, while still important, in excess can cause inﬂammation. Arachidonic acid is found in meat and dairy foods so don’t go overboard on them.
For cyclists, EFAs are particularly beneﬁcial as they have been shown to inﬂuence energy balance lowering levels of triglycerides (stored fats) and improving insulin sensitivity. This means more fat is burnt for energy while conserving carbohydrates. So this could even help with endurance training.
As they appear to boost metabolism they may aid weight loss. Omega 3 fats have also been shown to reduce inﬂammation, maintain joint and skin suppleness, support immune function and mental capacity.
Exactly how much fat you burn while cycling will depend on intensity and duration. During high intensity cycling our bodies mainly rely on carbohydrates (95 percent) with little from protein or fat.
However, with high intensity endurance cycling 15 percent or more of our energy will come from our fat stores. The more we train our bodies to use fat the more efﬁcient they become at burning it.
The current advice is that fat should make up between 25 and 35 percent of your calories. In a 2500Kcal diet this would be equivalent to 70-100g fat (1g fat contains nine calories). Aim to consume no more than 10 percent from saturated sources.
An optimum ratio for health is 3:1 Omega 6 to Omega 3. As most of us don’t consume enough Omega 3 oil in our diet it’s worth considering a daily supplement.
Top Omega 3 and 6 food sources
Omega 3 Foods: Flaxseed, pumpkin seed, walnuts, hemp seed, rapeseed, eggs, soya beans
Sources of DHA and EPA: Oily ﬁsh, e.g. salmon, trout, mackerel, herring, sardine, anchovies, fresh tuna and kippers
Omega 6 foods: Sesame, sunﬂower, safﬂ ower, corn, plus most nuts and seeds
Rich in GLA: Evening primrose oil, borage oil, blackcurrant seed oil
What about coconut oil?
Primarily made up of medium chain fatty acids, coconut oil is a popular, healthy fat for athletes. It can be metabolised efficiently, converting into energy rather than being stored as fat. This means it can form an excellent fuel source for all-day rides and endurance training as it is preferentially burnt for energy, thereby sparing muscle.
Coconut oil also contains lauric acid well known for its anti-microbial action and immune support. Being a saturated fat it is also safe to use for cooking – try it for sautéing or stir-frying, or use as a spread on toast.