Fire in the belly
'Almost every athlete has a nutrition mistake,' says cyclist Simon Chau, recalling his experience at the Tour of Hualien in Taiwan. Halfway through the 160 kilometre road race in 2005, Chau, 26, ran out of food.
He also hadn't eaten or drunk sufficient fluids during the previous day's travel from Hong Kong. With little in the way of stored energy, he barely made it to the finish line before collapsing - dehydrated, hungry and far from winning a prize.
Keeping body fuel topped up during exercise, whether it's a race or just a training session, has a huge impact on performance - particularly for an activity that lasts 90 minutes or longer. US-based sports dietitian Andrea Hacker-Thompson likens an athlete's body to a car. Beyond 90 minutes, a nutritional plan is needed to prevent the low-fuel light from turning on.
We're spoiled for choice when it comes to sports nutrition. In recent years, many new products come onto the market. This supply is in response to a demand fuelled by rising participation in endurance sports like marathons, triathlons and cycling, and a growing interest in general well-being.
According to the Nutrition Business Journal, the sports nutrition industry - which includes supplements, nutrition bars and gels, and sports and energy drinks and shots - has enjoyed a compound annual growth rate of more than 10 per cent over the past decade. Last year, global retail sales of sports nutrition products reached US$21.4 billion.
Of this, nutrition bars and gels contributed US$2.8 billion (a 13 per cent increase from 2010) and sports and energy drinks and shots US$15 billion (a 15 per cent increase).
But do we really need these shiny and expensive packets of gels, bars, chews and fluids? Not always. If you're trying to meet the recommended 30 minutes of moderate exercise a day, or running on the treadmill for only 60 minutes at a time, sports drinks or food are not needed during the workout.
'You are only taking on excess sugars,' says Dr Duncan Macfarlane, sports physiologist and professor at the Institute of Human Performance at University of Hong Kong. 'You are better off saving money and drinking water.'
But for anyone competing in high-intensity endurance activity, supplementing the body with the right nutrition during exercise not only ensures you will finish the event, it can also boost performance.
Hacker-Thompson, writing on the American College of Sports Medicine (ACSM) website (www.acsm.org), explains that the body of an endurance athlete is like a racing car with two fuel tanks.
In one tank are the body's fat stores, which contain about 70,000 calories of fat that are available during lower-intensity aerobic exercise. The other tank contains carbohydrates - stored as glycogen in the muscles and liver, and up to 2,000 calories at a time. As workout intensity increases, the body's ability to use fat as fuel decreases, and it becomes more dependent on carbohydrates for fuel.
'When your body runs out of glycogen, your race is over,' says Macfarlane. Known as 'hitting the wall' or 'bonking', glycogen depletion can turn any athlete, even a world champion, into a crawling mess in a matter of minutes.
A body depleted of glycogen can still function by tapping into fat stores for energy. But Macfarlane says these stores 'will only allow you to dawdle along'.
The ACSM recommends having a fuelling 'pit-stop' every 45 to 60 minutes during a long workout or race. This consists of 30 to 60 grams of carbohydrates (120 to 240 calories), as well as 180 to 355 ml of sports drink or water, every hour. Recommended mid-exercise foods, apart from sports energy products, include natural items such as honey, bananas and oranges.
But which is better, speciality sports nutrition or 'real' food?
Carbohydrate-rich food - such as a muesli bar, bread, banana or cookie - can provide energy for endurance exercise, says Stephen Wong Heung-sang, a registered nutritionist and professor of sports science and physical education at City University. But foods like this are less transportable and not as easy to eat on the go.
Sports nutrition products are typically more carbohydrate dense, easily digestible and come in convenient forms. The composition ensures you're not loading up your body with things that it can't process during exercise, like too much fibre.
That said, many athletes still swear by 'real' food such as bananas, nuts, dried fruit and baby potatoes, particularly as the duration of activity gets longer. Some just don't like the taste or texture of gels or bars, while others get stomach trouble due to the lack of solid food.
Jeremy Ritcey, one of the top trail runners in Hong Kong, says mixed bags of dried mango, apricot and almonds have worked 'fairly well' for him in training.
But he adds: 'I think the nutrition manufacturers have it down, though. Nothing packs a punch like some liquid gooey stuff.'
As for hydration, water alone is not enough, says Wong: 'When we sweat, we lose salts from our bodies as well as water.' Sports drinks are packed with the electrolytes sodium and potassium to replace what is lost through perspiration.
During moderate-to-hard exercise, the body is most efficient at processing fluids that have a carbohydrate concentration of six to eight per cent of its total volume. A good sports drink offers carbohydrates in this ratio, while sugary soft drinks may contain a higher ratio of up to 12 per cent carbohydrates.
Nutrition during prolonged exercise is important. But what you eat before the activity is equally crucial. That's because reliance on nutritional supplementation during an endurance sport can be decreased - and performance increased - with the right preparation, says Wong.
He recommends increasing carbohydrate intake to up to 75 per cent of total daily calories in the week leading up to race day to build up glycogen stores.
This could be in the form of sports nutrition products, though pasta, potatoes, bread and rice will work well, too.
Trail runner Nora Senn, 35, makes sure she eats a lot of healthy and nutritious food in the days leading up to a big race to strengthen her immune system.
She starts with the same ritual the morning of every race: two pieces of toast with butter and honey. Add a glass of juice, says Wong, and this combination is the perfect start for any endurance athlete's day.
Once your workout and race are finished, it's not all over. For 30 minutes after exercise, enzymes enabling the body to rebuild its glycogen stores run rampant.
'If you deprive your body of carbohydrates at this time it will extend the time that it takes for your body to rebuild itself in preparation for your next race,' says Wong. While it usually takes between 24 hours and three days to restore glycogen levels, a combination of amino acids and protein will expedite the recovery process.
With so many sports nutrition choices on the market, which is the best? 'It's very personal,' says Senn, who swears by Hammer Nutrition products. 'It's about taking the time to know the conditions and the environment you will be racing in. With experience, you can understand your body and know what the best combination is, so you can really go for it.'