How to Fuel for a Marathon

With just days to go until the Virgin Money London Marathon, now is the time to plan your marathon fuelling and hydration strategy. Worried about hitting the wall? Wondering whether to carb-load? Or how much water to drink during the race? Well, having a good fuelling plan will help you avoid the common marathon pitfalls. Here are some simple fuelling tips to ensure you make it to the finish line.

Days before
As you only have enough glycogen (stored carbohydrate) to fuel 18 – 20 miles of running, it makes sense to maximise your glycogen before the race and set off with as much fuel as possible.

This process of increasing your glycogen stores is called carbohydrate loading. It’s achieved by tapering your training during the final two or three weeks and then increasing your carbohydrate intake during the two days before the race.

It doesn’t mean eating mountains of pasta or indulging in whatever you want! You should keep your calories the same; but cut back on fat to compensate for the extra calories from carbohydrate you eat.

Include a source of healthy carbs like porridge, rice, potatoes, sweet potatoes or bread with each meal and add two or three high carb snacks, such as bananas, fruit and nut bars or flapjacks.

There no need to do a carbohydrate depletion phase. Studies have shown that tapering your training plus increasing carbs (8 – 12g/ kg BW/ day) for at least 2 days before race achieves just as good results. Realistically, a 70kg runner would need 560 – 700g carbohydrate.

The day before
By now, your muscle glycogen stores should be almost fully-stocked and you should be feeling rested. Your goals are to top-up your glycogen stores, stay well-hydrated and avoid any pitfalls that may jeopardise your performance the next day.

Eating little and often can be an easier strategy than eating big meals the day before the race so you don’t over-burden your stomach.

Stick with familiar foods. Eat only foods that you know agree with you and eat them in normal-sized amounts.

Steer clear of any foods that may upset your gut and jeopardise your performance on race day. Common culprits include pulses (beans, lentils and chickpeas), brassica vegetables (cauliflower, sprouts and broccoli), spicy dishes and high fibre cereals.

Get most of your carbohydrate during breakfast and lunch. Avoid blow-out meals or eating too late in the evening – no need for huge bowls of pasta! Overloading the night before a race can play havoc with your digestive system and keep you awake at night. You may also feel sluggish the next day.

Suitable meals include baked potato, chicken and vegetables; a simple pasta dish with salad; plain rice, fish and vegetables; or a turkey or tofu stir-fry with vegetables and noodles. Avoid heavy, hard-to-digest meals.

Aim to stay well-hydrated. Keep a water bottle handy so you remember to drink regularly throughout the day. This is especially important if you are travelling to the race venue on this day, as it is easy to forget to drink.

The simplest method to assess hydration status is to look at urine colour. From a practical point of view, you should be producing a dilute, pale-coloured urine. Concentrated, dark-coloured urine of a small volume indicates you are dehydrated and is a signal that you should drink more

Alcohol is a diuretic so it’s better to avoid it completely. If you overindulge, you may feel below par the next day.

Race day morning
By now, your muscle glycogen stores should be fully-stocked, and you should feel ready to go. All that remains to be done before the race is to top-up your liver glycogen stores at breakfast time (liver glycogen is normally depleted during the overnight fast) without feeling bloated, and replace fluids lost overnight.

You need to get up early enough to eat and digest your pre-race meal. Ideally, schedule your breakfast 3 – 4 hours before the race start time. So, if your race starts at 10 am, have breakfast at 6 – 7 am.

Fuel with a high-carbohydrate breakfast but stick with what you’re used to. Include a little protein or healthy fat to increase satiety and provide a more sustained energy release.

A bowl of porridge or oat-based cereal with bananas or berries; eggs on toast; or plain yogurt with fruit, nuts and granola are good options.

If you find it difficult to eat your normal breakfast because of pre-race nerves, try a liquid meal (such as a smoothie or milkshake) or a semi-solid meal such as yoghurt with chopped, pureed or mashed fruit. Bananas or porridge pots that simply require adding boiling water are good options if you need to eat on the go.

If you feel hungry, have a further carbohydrate-rich snack (25 – 50 g) about 30 – 60 minutes before the race. A banana, some dried fruit, a gel or a fruit & nut bar are good options.

Drink – but not too much!
Hydration is a fine balance. Don’t start the race dehydrated, but nor do you need to aggressively overhydrate beforehand. You don’t want to be making unnecessary pitstops early in the race!

As a rule, the ASCM advise 5 – 10ml of water/ kg BW in the 2 – 4 hours before the race. You can then sip small amounts, just enough to satisfy your thirst, during the 60 minutes before the gun goes off.

Should I take caffeine before the race?
A lot of runners like to use caffeine but only do this IF YOU’VE TRAINED WITH IT. It is tolerated differently by everyone and not everyone benefits, so don’t use it for the first time in a race.

Caffeine is a stimulant; it may improve performance by lowering your perception of fatigue and pain. A general recommendation is 1 – 3 mg/ kg body weight, or about 100 – 200mg. You can take it as coffee, gels or pills. A single expresso contains 75mg, one caffeine gel contains 25 – 75 mg and caffeine pills 50mg (check the label though).

It takes 30 – 60 minutes to peak in your bloodstream so you can either take your caffeine shortly before the start or towards the latter stages of a marathon if you want a boost for the final few miles.

Fuel during the race
You won’t have sufficient glycogen to fuel you 26.2 miles, so you’ll need to refuel approximately every 30 – 45 minutes. Start fuelling after about 60 minutes. Don’t wait until you feel exhausted or hit the wall otherwise your gut may reject the food and it will come straight back up.

Check in advance where feeding and drinks stations are on the route, so you can plan when to refuel. At the VM London Marathon you’ll find water at 1 mile intervals, Lucozade Sports Drink at miles 5, 10, 15, 19 & 23 and Lucozade gels at mile 14 and 21. Stick to what you’ve trained with and only use what’s provided if you have trained with it.

The ideal intake is 30 – 60g carbohydrate per hour, depending on your pace (and your gut). Use whatever you trained with and can stash easily in your pockets or belt.

You can either get your carbs from sports drinks, a combination of foods and water, or a combination of all of these. Foods containing 30g carbohydrate include 40g raisins, 2 Medjool dates, 2 Energy Balls, 2 small fruit and nut bars, 6 jelly babies, 1 large banana, 500 ml isotonic sports drink, roughly 1 energy gel (most provide 25g) or 1 energy bar.

Other options include fruit and nuts, which increase blood sugar more gradually due to the presence of protein and fats. If you prefer the convenience of gels, bars and chews, take them with a few sips of water to dilute the high sugar content.

Drink to thirst
During the marathon, there are no strict rules about how much to drink as this depends on how much fluid you lose through sweat. The International Marathon Medical Directors Association suggest 400-800ml of fluid per hour, depending on your sweat rate.

If you’ve practised a drinking strategy in training, you probably have a good idea how much to drink but if its warmer or colder than expected, then you will need to adjust your plan.

Don’t drink excessively. Drinking more than you’ve lost increases the risk of hyponatraemia (low levels of sodium in the blood), which is a serious and potentially fatal condition. As a rough guide, aim to drink 125–250 ml –about two or three big swigs – every 15 to 20 minutes or according to thirst.

You don’t need to drink at every aid station but don’t be tempted to miss out the early fluid stations to gain valuable time, particularly on a warm humid day – dehydration later on will slow you down even more. Slowing a little as you run through the stops while drinking may add 1 or 2 minutes to your time but it can repay you with 10 or 20 minutes gained by the finish of the marathon.

Stick with whatever you have used in training and don’t try anything new. Continue drinking until the last few miles.

After the race
Before you go off and celebrate, you need to replace the fluid you have lost. Drink around 500 ml, little and often, in the first 30 minutes after the race, and then keep sipping every 5 to 10 minutes until you are passing pale coloured urine again.

You also need to start replenishing your glycogen stores, ideally 1g carbohydrate/ kg BW. To promote muscle repair, consume around 20g protein. Milk (dairy or soya) or other milk-based drinks or recovery drinks, yogurt, bananas, peanut butter sandwiches, home-made super-flapjacks, blueberry muffins or fruit and nut loaf are good options.

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