Good Nutrition For Runners: By Serene Seng, a Nutritionist

Nutritionist Serene Seng gives a talk to ST Run participants.

Nutritionist Serene Seng gives a talk to ST Run participants.

What type of foods are good to eat just before a marathon race – to avoid running into digestive problems on race-day? And should you be drinking that post-race celebratory beer?

The marathon runners participating in this year’s Straits Times Run at the Hub on 28 September got the answers to these – and also received other nutrition tips in a talk at Suntec City yesterday – from nutritionist Serene Seng, who is in private practice.

At the talk, targeted for the participants of the Straits Times Run this year, but which is also part of the Health and You exhibition (organised by the Straits Times), Sng shared a myriad of nutritional-related information related specifically to running.

Here are the main highlights that the nutritionist shared with participants.

General Nutrition Guidelines for Runners


Generally, the amount of carbohydrates that a distance runner should preferably consume is about one to 1.2 grams of carbohydrates per kilogram of body weight over a 24-hour period – following a training session. So a 70kg man should consume 70 grams of carbohydrates daily – this is equivalent to roughly two standard bowls of rice.

As well, Seng says that it is important to replenish the depleted carbohydrates inside your body within four hours of completing a hard training session – especially if you are training again within the next 24 hours.

This is because the absorption of carbohydrates as well as the building of glycogen stores is especially accelerated in the first four hours of the commencement of an exercise session.


Proteins are useful too, because they help with muscle building in athletes. But they can cause calcium loss and dehydration if they are eaten in excess – which unfortunately, some runners may tend to do.

A distance runner who trains and exercises several times a week typically requires 1.2 grams of proteins per kilogram of body weight per day. So for a 50kg man, that would be about 60 grams of proteins.

Vitamins and Minerals

The nutritionist feels that a vast majority of distance runners may lack certain nutrients.

Lack of calcium is a common problem amongst female athletes as they need between 1,200 to 1,500mg of calcium per day – but some do not get enough.

Iron is also a common deficiency amongst athletes, especially females, and this will prevent them from being able to build muscles. This may happen to athletes who train a lot. You know that you may be having a lack of iron, if you cannot focus or concentrate at work – but on the other hand, you may not have trouble concentrating during training sessions.

However, it must be noted that iron and calcium should not be taken together because the iron would not be absorbed easily into the body with the calcium. Instead, try and take iron together with food rich in vitamin C – such as orange juice.

A lack of magnesium, according to Sng, also commonly leads to cramping and painful joints during or after exercising. Eating foods such as beans, nuts and legumes would give you more magnesium.


Taking fluids are especially important to runners, who lose plenty of water through sweating. However, at the same time, try not to consume too much water – especially during a race, because this can cause you to feel very bloated or uncomfortable when running.

The general rule of thumb for race hydration is to consume one small glass of water after every 10 to 15 minutes of training. However, the exact amount will depend on the individual, though. Do take note that people who tend to sweat probably need more fluids than those who don’t sweat much.

Preferably, if you want to find out exactly how much fluid your body needs during a workout, you should do so before and after a hard training session. For example, if you find that you have lost more than two per cent of your body weight after a workout, you would then need more fluids. But if you have gained weight immediately after training, you may be drinking too much.

Pre, During and Post Race Nutrition Guidelines for Runners

Pre Race

For marathoners, a common practice known as Carbo-loading is very important. This is because the body burns carbohydrates to give the body energy to run the marathon.

So you need to eat lots of carbs before a race. Typically, you should consume nine to 12 grams of carbohydrates per kilogram of body weight per day – about one to three days prior to race day. This should preferably be foods with high Glycaemic Index (GI), such as white bread, white rice or refined pasta, which is digested easily.

As well, about two to three hours before the race itself, you also need to prime the body to use the carbs stored – by consuming a light snack. This can be a banana, a handful of jellybeans or a couple of chocolate squares. If you are not hungry, a glucose solution or isotonic beverage would also be good to drink.

Between this time period hydration is very important. So you would preferably need to drink two to three glasses of water about one to one and a half hours before the race.

Hydration is important to runners.

Hydration is important to runners.

During the Race

A marathon is a long race that may last a number of hours for some. So it is important to ensure that you are sufficiently hydrated and have enough carbs to last the distance – or you may collapse.

Drinking a glass of water or sports drink every 10 to 15 minutes of running is recommended. Altogether, you should consume about two to four litres of water during the course of the entire marathon.

You should also take food, such as an energy bar, nuts or whey proteins to boost your performance. Consuming half-cooked egg whites are also a good source of proteins during the marathon – to help with muscle repairs.

However, that said, Sng strongly urges runners not to force themselves to eat or drink anything they are not familiar with, or don’t like, for energy refuelling. For example, not all runners are fond of protein shakes and energy gels – so don’t make yourself consume these. Only eat and drink foods that would not affect your stomach and cause problems during the race – that is, stick to consuming familiar foods that you enjoy.

Post Race

After a marathon, the last thing that you should do is to go for that celebratory beer, because your body has already been damaged from running a marathon – and the beer would damage it even more.

Instead, you should immediately consume a small amount of sodium, followed by carbohydrates. Try and take these nutrients through a drink, if you are not feeling very hungry. For example, taking sports drinks are good to replenish the lost nutrients, such as salts from your body.

However, unlike athletes competing in power sports like sprinting, it is not necessary for marathoners to eat a lot of carbohydrates after the race, because most likely, they are not going to be running another marathon again for a few months at least – so the body would have plenty of time to recover and replenish its stores.

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