Nutrition for Marathon Race Day
Below are some important considerations to ensure that you have the best possible race on the 18th of September.
Do I need to carb load?
For a marathon distance race it is beneficial to “carb load” for 2-3 days prior to ensure your glycogen stores (in your muscles) are full and ready to power your over the 42km distance, and delay to onset of fatigue.
This does not meaning increasing meal size, or calories, but ensuring that each meal does contain predominately carbohydrates, along with a small amount of protein and healthy fat. Vegetables, fruit, legumes and whole grains are excellent sources of carbohydrates. You may find your weight increases over these few days, as carbohydrates store extra water in your cells – don’t worry, you’ll need the extra water on race day.
Should I drink extra water?
Yes. Hydration levels are critical for athletes, and you should arrive at the race fully hydrated. You should be drinking 2 litres of water a day for 3 days prior to your race, adding a pinch of salt to help increase the uptake of water into the cells. You can also use electrolyte replacement tablets or sports drinks that have electrolytes in them to help increase hydration levels.
What should I have for breakfast?
You may feel very nervous on race day morning. Now is NOT the time to consume anything new – (food or fluids) even if it’s free or your friend highly recommends it.
A light breakfast 2 hours prior to the race is ideal - it should be mostly carbohydrates, and around 1-2grams of carb per kilo of body weight.
Eg; if you weigh 60kgs, your breakfast should be 60-120 grams of carbohydrates. If you don’t have much time before the race, stick to the lower end of this scale.
The meal should be low in fibre, low in fat and low in protein, to decrease the risk of gastric upset.
Eg: Banana, White bread, crumpets, honey, fruit juice, sports bar.
30 Grams of carbs:
1 medium banana
2 slices white bread
2 Tbs honey
1 gel (check label, usually 20-30gms)
Sports Drink – check label
It is not advisable that you drink sports drink for the hour before the race. Just have your breakfast, and then sip on water. Just prior to the start (i.e. 10-15 mins) you can have a gel if you like.
Fuelling during the race:
By race day you should have practiced a fuelling strategy, and know exactly what your race day nutrition plan is. Do not leave it until the night before the race to figure out, or worse still – “wing it” on the day.
How much do you need?
Most runners will need between 30-45 grams of carbohydrates (fuel) per hour over this distance. Some runners may need a little more (up to 60grams per hour). This can come from sports drinks, gels, chews, bars, or real food. Read the label on the product and figure out how much you will need. Your gut is only able to absorb a certain amount of carbs at one time - so it’s best to consume them 2-3 times during the hour. Setting an alarm on your watch to beep every 20- 30 mins is a great way to remember to take some carbs /fuel on board.
Some people are happy with just one source of fuel (i.e. gels), others find that having a combination works better for them (i.e. Gels/energy bars/chews). It is vital that you have tried and practiced with difference sources of fuel, different brands, and different flavours to determine your perfect race day plan. Part of your training is to train your gut to absorb the carbs whilst running. If you are new to endurance sport, you may find that 45gms of carbs per hour is too much – and you need to build up to this. The ideal amount of carbs is enough to make you feel energised but not too much that it causes GI distress. If you are “hitting the wall” or “bonking” during training, then you are not consuming enough fuel.
Gels are very convenient to carry and consume during marathon – however make sure you consume them with 250ml of water, or they will not absorb effectively and may cause an upset stomach.
Trial and error during training runs is the best way to figure it out your race day plan – once you’ve found what works for you, stick with it.
This is an extremely important part of your nutrition strategy that is often overlooked.
The amount of water you lose during a race is very individual and also dependent on the weather. Ideally you will have already calculated your hourly sweat rate, and know how much you lose. If you don’t know your sweat rate – a guideline is around 600 -750mls per hour for most people.
Faster runners will struggle to get this amount in over the course of the race, but it is vital not to become dehydrated. Try to drink at all aid stations throughout the race.
Slower runners are generally better at consuming water during the race, and hence the issue of hyponatremia needs to be considered. This is when the level of sodium in your blood is too low and your body can no longer regulate the amount of water in your cells. To overcome this, you need to consume sodium (and other electrolytes) during the race, and be sure not to “over hydrate”.
You need to replenish glycogen stores (carbohydrates), plus some protein for muscle recovery. This should be in the ratio 4:1 Carb:Protein
Sports recovery drinks/bars designed for this are great in a race situation as they are very portable and you may not have access to your regular recovery meal, or you may not like what is available at the finish line. Have a member of your support crew bring something along for you to have at the completion of the race.
Alcohol is not a good source of hydration. Makes sure you hydrate and re-fuel properly before celebrations begin!
Enjoy your race!
Mad on Nutrition offers face to face or Skype appointments if you would like personalised help to determine your race day plan, or improve on your every day nutrition.
Tamara is a qualified clinical nutritionist - specialising in endurance sports, and she is also an experienced endurance runner.