Many first-time marathon runners and those wanting to improve their marathon time, are often overwhelmed by the sheer volume of information available about fuelling for marathons. This article is the first in a short series of nutrition and fuelling strategies for the standard 26.2 miles / 42.2 km marathon and also for ultra marathons.
There are many excellent detailed studies available which can be incredibly informative for those who want to study things in more depth. These can be "heavy going" for a mere mortal with little spare time, who really just wants to run, and feel good while they are doing it!
Here we will try and keep things simple. We will deal with some general nutritional guidelines for marathons in this first article, plus some specifics for immediately before, during and after your marathon race.
Future articles will go into more detail on some aspects of nutrition and fuelling for marathons and ultras, and deal with short-to-medium ultras of up to 50 miles and 100km, then the longer ultras of 100 miles and 24 hours which are becoming increasingly popular. Then there is the more specialised zone of the multi-day events.
Adapting your Nutrition for Marathon Training
Whatever sport you take part in, if you are training regularly, and - as in the case of training for a marathon - you are steadily increasing the volume and workload, you are asking more of your body, and it is important to understand this.
Imagine if you were a car. The fuel and maintenance needed for short journeys around town or country is minimal to what you need for regular long journeys. Although the body has a seemingly miraculous way of adapting up to a point when you ask more of it, like a car, if you don't refuel and maintain it, it will run out of fuel eventually and start misbehaving or come to a complete standstill.
Carbohydrate and the GI Index for Runners
Carbohydrate is the main body fuel, along with protein and fat. Most runners understand the importance of eating a lot of carbohydrate. The key to re-fuelling well and consequently training well over a period of time, can be influenced by the type of carbohydrate eaten. Readers will probably be familiar with the terms refined and unrefined carbohydrates. These have been defined more clearly with the development by sport scientists and dieticians of the Glycemic Index (GI).
The GI grades carbohydrates on a scale of 1-100. Refined or simple carbohydrates, high on the GI index, are rapidly digested and absorbed by the body, and result in a quick increase in blood insulin concentrations. Unrefined or complex carbohydrates are lower on the GI index, absorbed more slowly, giving a slower build-up of blood insulin levels.
Why, might you ask, should I be concerned about blood insulin levels? Well simply put, the aim in training over a period of time is to try and maintain a steady level of blood insulin levels and not have a yo-yo effect where the levels are rising and falling. Foods that are low on the GI list are more likely to help keep your blood glucose levels stable and give a steady supply of energy, which is great for the overall picture through the weeks of training.
Foods that are high on the GI index are more likely to cause the yo-yo effect. That is not to say they are totally bad. From a performance and training point of view, they can be useful when a quick burst of energy is needed on a hard training effort or a long run, or when used purposefully on race day itself.
Examples of high GI foods are cakes, biscuits, glucose and white bread. Examples of low GI foods, which are more slow release are porridge, most vegetables, grains, nuts and wholemeal bread. Nutrition is a vast subject that we cover in the Running Nutrition section of this site as well, but the old adage of a good all-round diet with plenty of fruit and veg still holds sound.
The Week or so Before Your Race
Much has been written over the years about carbohydrate intake in the week before a marathon event, some of it conflicting. The legendary British marathon runner Ron Hill was one of the first advocates of the carbo-loading diet and its effectiveness still creates much discussion amongst experienced coaches and runners. So what should you be eating in the final week before your race and is there any merit in what has become known as carbo-loading?
The body's two main energy sources are fats and carbohydrate. Carbohydrate is stored as glycogen in the body and this is more readily available to use as energy than fat. So that is why you constantly hear the marathon runner's mantra of "eat more carbs", and why in the 3-4 days before a marathon or an ultra race, you need to load your body with extra carbohydrates. In normal training, if you build things up slowly, you can usually run for 90 minutes without having to draw too much on extra reserves. The longer you exercise, the more these natural stores are depleted, leading you to draw on extra carbohydrate supplies. When these are exhausted, your body starts burning fat. We have all had the experience of energy fade at the end of longer training runs!
The essence of the original carbo-loading diet was that on the weekend before your race, you went for a steady run that would leave you feeling tired, and would deplete the system somewhat. The 3 days after this (Mon, Tues, Weds) were days where the diet was low in carbohydrate but high in protein and fat. Also you continue training at a moderate level. After the 3 days of low carbohydrate, your body is almost demanding more. So on the Thursday, Friday and Saturday, or the 3 days before your race, you do the reverse and increase the carbohydrate intake while reducing the fats, and at the same time really reduce your training right down. This ensures you are fully loaded with glycogen for your muscles to draw on, on race day.
Although some elite and club level athletes still use the dedicated carbo-loading regime, many runners (especially mere mortals just wishing to finish or improve their previous times a little on their last race), use a modified version. This involves just increasing the carbohydrate intake in the 3 days before the race, resulting in a boost to the glycogen stored in the muscles and the liver.
So can one eat any carbohydrate to one's heart's content? Unfortunately no, not if you want to perform to your best, whatever your standard. If you stuff yourself needlessly, you will just feel bloated, so strike a balance between eating well and going over the top. It is a good idea to experiment eating a lot more carbs, on the day or two before one of your long training runs. Also if your race has an early start, don't eat too late in the evening, or it will not have a chance to fully digest, and will still be lying in your stomach in the morning! If possible try and emulate the start time of the race on one of your training runs too. This will allow you to see how you react and benefit.
Foods such as pasta, potatoes, bread and rice, which are high in starch, should increase your body's glycogen supply. Some protein and fat is also beneficial, but try going easy on high dairy foods like cheese sauce with pasta, go for a lighter tomato based option instead. If you just can't face eating huge portions of pasta and potatoes, try an energy drink rich in carbs, like SIS Go Energy or High 5 Energy Source. This will still vastly increase your carbohydrate intake in liquid form, and although everyone is different, should avoid the heavy feeling of a big meal.
As far as regular fluid intake is concerned, it goes without saying that your aim is to go to the start line, as before all your long training runs, well hydrated. You don't want to change too much from your training routine for race weekend, but an extra litre or two of fluid for the 3 days before your race will definitely help. If you prefer, adding an electrolyte tablet like like or High 5 Zero, in a fairly weak solution, will ensure both fluid and the body's natural electrolytes (like sodium and potassium that are lost in sweat) are also well topped up.
Nutrition for Race Weekend Itself
A light breakfast a couple of hours before the start is good to ensure you have a full fuel tank. Some wholemeal toast (low GI) with a banana is perfect, as is the need to keep sipping fluid regularly. Do practice this routine on your long training run days, to simulate race start time.
Nutrition for Post-Marathon Recovery
The best and simplest advice is that recovery starts as soon as you cross the finishing line of your race. This is true for training runs as well. Have a drink or snack ready to start consuming within minutes of finishing, as soon as you have settled down. High GI (sugary) snacks are good here to give a quick boost. It will really start (and speed up) the recovery process.