The longer the distance, the more crucial correct nutritional planning is to enable you to finish a race, though even for a 5k it is very important to eat and drink correctly. Preparation beforehand is important, as is the recovery period following a race.
As an active person I aim to drink at least three litres of water daily
In general, try to get into the habit of drinking little and often throughout the day. As an active person I drink at least three litres of water daily. Practice drinking and eating on the run in your hard training sessions. Don't experiment with different products on race day.
The week before
I carbo-load the week before a race and eat little and often, alternating snacks with main meals and aiming to increase my carbohydrate intake to approximately 70% of my total.
On race day
It's important to keep hydrated on race day
On race day I get up at least two hours before the race and have a high carbohydrate snack of about 300 calories, at least an hour before the race. Ideally I eat a high carbohydrate meal 3-4 hours before the race. I drink enough so that urine is clear just before the race.
During the race
It is always advisable to take a drink at aid stations if provided - better to drink even a little, than to have to stop and drain a cupful because you are thirsty. Drink regularly and avoid gulping the water so as to avoid a stitch. If it is a hot day then drink a little more at each station. I aim to consume about a litre of liquid per hour of exercise.
Some races do not have water stations at all. This should be fine if the race lasts less than an hour, you can be well-hydrated before the start and start re-hydrating immediately you finish.
Racing with a hand held bottle © Sarah Stirling
For any race over an hour you may want to take a hand held bottle to enable you to drink when necessary as your race performance will get worse as you dehydrate. Once you have lost more than a kilogram of body weight, your temperature and pulse can start to rise, forcing you to slow down.
If you are racing for over an hour (usually longer than 10k) you should replace lost energy by eating. If you can't manage regular solid food, longer races can be run easily on energy supplements like energy bars, gel and carbohydrate or sports drinks. Start taking these after 30 minutes and I would continue to take between 30-60 grams of carbohydrate per hour.
Athletes who run sub three hours for a marathon will often avoid solid food - when running for longer many people feel the need for it, though it is possible to race these distances with just gels etc.
During races you may find sponge stations. These will provide you with a great way to cool down and help you get through a hot days racing. Use sponges on your head, under the arms, on the back of your neck and forehead. Again take one each time they are available, as lowering your temperature can slow down dehydration and keep your pulse lower.
After the race
In the two hours after the race I try to eat a high carbohydrate meal with some protein and continue eating high carb snacks and meals for the rest of the day.