I have always felt that a balanced diet covers all our needs, and extras such as vitamin pills, protein supplements or energy drinks are unnecessary.
However, the nature of the marathon means that extra attention is needed to ensure that you don’t run out of energy on the day. But in this post I will be highlighting the basic principles needed to develop an effective and realistic marathon diet plan for the whole training period rather than race day itself, which will be dealt with in another post.
When considering the diet for an endurance activity, there is naturally an emphasis on carbohydrates as the prime food source, since you need a good supply of glycogen to power your muscles for a prolonged period. But you also need plenty of protein to enable muscle tissues to repair effectively after each workout, some fat as an alternative energy source and to allow the absorption of the fat soluble vitamins, fibre to maintain healthy intestines, and also foods that contain antioxidants, which help mop up the extra free radicals that can be produced when we respire more rapidly. The good news is that a relatively normal well-balanced diet, perhaps chosen with a little extra thought, will cover all these bases. So let’s have a brief look at all the key components of a well-balanced diet that, along with a sensible training and recovery schedule, should give you a good chance of achieving your race goals.
Carbohydrates can be classified as simple or complex. Simple carbohydrates are basically sugars such as sucrose (ordinary sugar), glucose or fructose. As these require little or no digestion, they give a quick release of energy when required, and therefore can be very useful during the marathon as part of an energy drink or gel, or in sweets such as jelly babies. Most of the time, however, it is much healthier to consume complex carbohydrates, as they need to be broken down by digestion and so allow a slow and steady release of energy without rotting your teeth of giving rise to a sugar rush.
Potatoes, pasta, rice, bread and cereals are perhaps the most common go to guys for complex carbohydrate, and they all do the job effectively. However, most dieticians would recommend focussing on less processed carbohydrate sources, such as potatoes, brown rice, quinoa and beans rather than white pasta and bread, which are the result of wheat processing. Quinoa and beans are also good sources of protein. Wholegrain bread, rice and pasta are healthier than those made from white flour, as they contain fibre and a whole lot (like the pun?) of other important nutrients. Oats are another good source of carbohydrate and also contain a significant amount of protein, plus a variety of vitamins, minerals and antioxidants. And don’t forget bananas, which have the advantage of needing no preparation, as well as being a great source of fibre and potassium.
Protein is needed to build and repair muscle tissue, so perhaps the easiest way to get this protein is to eat the muscles of another animal, ie. meat or fish. I personally try to avoid red meat as I believe that beef production in particular is very bad for the environment and the health drawbacks (eg. the production of bad cholesterol) outweigh any advantages. Fish (especially oily fish such as salmon, trout or mackerel), chicken and eggs are excellent non-vegan options, whilst lentils and the previously mentioned beans and quinoa are among the choices that are acceptable to everyone. Most of these foods will go at least some of the way to replacing not just the protein, but the essential vitamins and minerals (eg. iron and the B vitamins) that come with red meat.
We need some fat, as an energy source but also to supply us with fat soluble vitamins such as A and E, but the majority of people have too much fat in their diet, hence the obesity crisis. And it’s not just that people eat too much fat, but that they are eating the wrong type of fat – the ‘bad fat’.
The ‘bad fats’ are saturated fats, found in animal fat and therefore lard and butter (and other dairy products such as cheese) and more surprisingly in coconut oil and palm oil (so palm oil production isn’t just a disaster for the rainforests, but it’s not great for human health too). The ‘good fats’ are unsaturated fats, and these are found in almost all plant based oils (eg olive oil, sunflower oil, sesame oil and various nut oils) as well as avocados and most nuts. Peanut butter is obviously a good source, but often it contains added palm oil, so watch out for this and be prepared to pay a little more to get the palm oil free option. Oily fish, such as salmon, trout and mackerel, are also excellent sources of unsaturated fats, and also boast long chain omega 3 molecules, which have a range of key roles, including the maintenance of low blood pressure.
Pre-race nerves are very effective at promoting bowel clearance, but a longer term solution requires a diet containing plenty of fibre. The simple answer is to eat lots of fruit and vegetables and wholegrains (in eg. cereals and bread). These foods tend to have a variety of other health benefits, including antioxidant effects (see below), so it really is worthwhile having your five (or more) a day.
Antioxidants are molecules that do exactly what it says on the tin – counteract oxidation in the body, a process that is more likely to occur when we exercise aerobically. They do this by mopping up harmful free radicals, the particles that are believed to cause mutations of DNA and potentially increase the risk of cancer and other diseases. Foods that are high in antioxidants include green leafy vegetables such as kale and spinach (Popeye was onto something), fruits, carrots, whole grains, oily fish, seafood and lean meats, as they contain important minerals such as zinc, iron, magnesium and copper, and vitamins such as C and E.
Affordability and convenience
It’s very easy to give advice on what you should and shouldn’t eat. However, financial and time constraints can make it difficult to follow all the suggestions. Healthy options are not always the cheapest options, and fresh fruit and vegetables, oily fish and nuts, for example, can be relatively expensive. But you may find that beans of various types can be more affordable and can cover much of your protein needs. Bananas, potatoes, rice and pasta are also usually relatively inexpensive, and remember that you don’t need much meat or fish in your diet to cover your protein needs, especially if you eat lots of beans, lentils, etc. A breakfast including porridge oats is another cheap and effective choice. The thing is do what you can. Any positive changes, however small, are potentially beneficial. For example, if your lunchtime cheese sandwich made with white bread is replaced by peanut butter on wholemeal bread, and you follow it with an apple or other fruit instead of a chocolate bar or biscuit, then that’s progress.