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October 3, 2011
It’s just under a month now until the 262km of pain that is the Melbourne-Warrnambool. There are also a host of similar one day classics around Australia such as the 228km Grafton-Inverell and the just gone 208km Launceston-New Norfolk. No matter whether your aim is to win the thing, have some fun or just survive to the finish, here’s some nutrition information that might help you achieve that goal.
I’m not going to touch on the specifics of riding when tapering, but nutrition in the days before the race is just as important. This of course is your carb loading, making sure you start the race with a full tank. As mentioned in a previous post carb loading properly should make a difference of 3-4%.
I’m not going to re-write an article about carbohydrate loading except to say that it requires a massive increase in carbs (and total food volume) for most people. Some elite riders eat this quantity frequently so it’s not a big deal for them, but for most of us it requires careful planning and a lot of stuffing yourself full with starch and sugar.
To look at exactly what carb loading looks like here’s the AIS fact sheet on the topic. But a few key points:
• Everything you put in your mouth during this time has to be chosen to be high in carbohydrate and low in fat, fibre and protein.
• Refined, sugary foods are perfect – they’re not too filling. Large quantities of low fibre food will still add up to a normal daily fibre intake.
• Get carbs along with the water in your fluids. Go for juice, cordial and soft drink. This would obviously not be recommended for everyday eating, but a couple of days before a race in an otherwise healthy athlete is fine.
Finally there’s the issue of what’s the best way to carb load. Protocols from the 70’s and 80’s used depletion (very low carb diet) followed by three days of high carb eating. However research shows this isn’t necessary. The focus shifted to whether you need to carb load over multiple days, or if a single day is sufficient. A study in 2002 asked participants (8 male competitive but not elite cyclists or triathletes) to eat 10g/kg/day of carbs for three days. They found a large increase in carbohydrate (glycogen) storage at the end of day 1, but no further increase afterwards.
Source: Bussau et al. Carbohydrate loading in human muscle: an improved 1 day protocol. Eur J Appl Physiol (2002) 87: 290–295.
I should point out though that the entire recommendation of one-day carb loading is based on one study of 8 athletes. We don’t know if it’s repeatable, if the result applies equally to all athletes, or if the result would be different in females. For the Warny or the Grafton I’d hedge my bets and suggest a two day carb load.
The morning of the race
What you eat in the few hours before a race start isn’t actually that important, provided you’ve carb loaded properly. At this stage you’re muscles are stocked with carbs already so it’s all about comfort. Choose low fat snacks with some carbohydrate in them such as cereal or toast, but don’t worry about exactly how much or what it is. Some people don’t like to eat solid foods before a race – instead you can try liquids such as Sustagen or Up & Go.
During the race
This is where you can make a big difference to your race. Carbohydrate has a dose response effect, so the more you consume the quicker you can go. In the last couple of years the term “carbohydrate availability” has been used to describe how much you’ve got to use over the course of a race. This is a combination of what you’ve stored from loading, plus whatever you consume during the race. The rate you use carbs depends on the intensity you’re riding at (the harder you go, the more carbs you’ll use). If you go too hard and run out before the finish your last resort is to use your blood sugar. If this drops too low then you’re going to hit the wall (or “bonk” or “hunger flat”, depending on the local lingo). So the greater the carbohydrate availability, the harder you can push the pace without bonking.
How much can you eat in a race situation will be dictated by what you can physically absorb and what’s practical to carry and consume. In an event like the Warny or the Grafton, I’d aim for a MINIMUM of 60 grams an hour, and more if you can. If you can get up around 90-100g an hour you’re going to have a definite edge over most riders. You’ll notice I haven’t specified carb intake in grams per kg per hour – that’s because the rate of absorption from the gut is the limiting factor, and isn’t related to body weight.
If you consume over 60g an hour of carbs then the type of carbs becomes important too. All carbohydrate we eat is digested into three sugars – glucose, fructose and galactose. These are then absorbed through transporters in the intestinal wall. Galactose is not an efficient energy source, and not relevant to this discussion. Researchers showed that whilst glucose absorption is maximised at about 60 grams an hour, fructose is absorbed separately and can increase total absorption well over 90g an hour.
What does that look like in food?
Firstly, we know that it doesn’t matter if your carbohydrate comes from drinks, gels or bars. Secondly, the majority (but not all) of products already contain some combination of glucose and fructose. A couple of brands produce some or all of their products based in a 2:1 ratio of glucose-to-fructose (once digested). However it’s the total amount of each sugar (not the ratio) that’s important.
Let’s have a look at the carbohydrate content of sports nutrition products:
• Sports Drinks: Generally a 6% carbohydrate drink (6g of carbs for every 100mL).
• Sports Bars: Usually 35-45g of carbs
• Sports Gels: 20-30g per gel
So to consume 90g of carbs an hour you’d need a combination like this:
• Water plus 3-4 gels an hour OR
• 500mL of 6% sports drink plus 2 gels an hour (additional water as needed)
That’s not necessarily realistic (or cheap) for a race of over 6 hours. My suggestion if you can tolerate it is to make your sports drink at 1 ½ strength (9%) or even double strength (12%). Then the equation becomes much more practical:
• 500mL of 9% sports drink plus 1 bar an hour (or 3 gels every 2 hours)
• 500mL of 12% sports drink plus 1 gel an hour (or 1 ½ bars every 2 hours)
What about hydration?
As mentioned in a previous post the jury is very much still out. Traditionally studies compared no fluid intake to large fluid intakes that prevent weight loss of over 2% during exercise. But the question should be whether drinking less (but enough to satisfy your thirst) is just as beneficial. Studies examining this question have only been done in exercise of up to two hours – they showed that drinking more than thirst made no difference.
In a lot of ways the argument is pointless, because sports drinks also provide carbohydrate. So for the Warny I’d aim for around 500mL an hour as above, but carry extra fluid so if you’re feeling thirsty you can drink more.
To caffeinate or not to caffeinate?
Generally speaking caffeine will improve performance by 2-5%. It takes up to an hour for caffeine to take effect once ingested, and lasts in the system for 4-6 hours. The most commonly studied beneficial dose is 3mg per kg of body weight (210mg for a 70kg rider). The caffeine content of a coffee varies enormously (50-200mg), a can of Coke has 40mg, a Red Bull 80mg, No Doz tablets provide 100mg each, and caffeinated gels vary by brand (10-80mg).
If you’re someone that gets nervous before a race, or someone who doesn’t tolerate caffeine well then it may not be the best idea to take any at the start. You might wait til halfway through. If you do take caffeine straight away, be aware that you might need more later on, because it’ll wear off by the six hour mark.
Practice makes perfect
Finally, it’s important to try any new nutrition regimen in training first. Taking a large dose of caffeine untested, upping the ante with your carb loading, or squeezing down double your usual number of gels may take a bit of getting used to. You’d hate to ruin your race because you tried something for the first time and it went pear-shaped. Use longer training rides to try these strategies and tweak them if required. That way you’ll turn up to the start line confident in what you’re doing, knowing what to expect.
Ask an expert – for free
[CyclingTips] If you’re in Melbourne on Friday 14th of October, Sports Dietitians Australia is hosting a free public lecture at BMW Edge at Federation Square from 6.30pm. The session will look at the evolution of sports nutrition in Australia, from the 80’s when the goal was to get footy players to drink water rather than beer after a match, through to today’s cutting edge science. Most sports dietitians in the country will be there, including the AIS Nutrition team (who look after our national track and road teams). You’ll have a rare chance to fire questions at these guys so I’d encourage you to get along if you can. I’ll definitely be attending. For more information go to http://www.sportsdietitians.com.au/2011conference