THE NEW RULES OF FUELLING
Carb-loading benefits are real. Follow these new rules to perform at your best on long runs and in big races
THE ADVANTAGES of carbloading have long been clear: when researchers tracked more than 250 runners before the 2009 London Marathon, those who carb-loaded finished, on average, 13.4 per cent faster than those who didn’t, regardless of age, gender, weight, training or experience. They were also better at maintaining race speed.
Carb-loading is a no-brainer, but the best way to optimise carbohydrate consumption is less straightforward. Scientific understanding has evolved since carb-loading became a thing back in 1967, but it’s hard to keep up to date on the latest and best practices. To help you out, here’s a definitive guide to maxing out your carb storage so you ensure peak performance.
• WHY CARBS COUNT
You know carbs are important, but here’s a quick refresher on the science of why: the moment you spring into motion, your body starts burning fat and carbohydrates to power your muscles. Fat takes more energy and oxygen to burn, so it’s only good for easy efforts. As you work harder and start huffing and puffing, you’re not getting in enough oxygen to burn fat, so your muscles start tapping into your stored carbs (aka glycogen) for quick-burning fuel.
Though even the lean Kipchoges of the world have nearly unlimited fat stores, everyone’s glycogen stores are limited. Research shows you can store between 1,500 and 3,000 calories’ worth, depending how much muscle you have, says sports physiologist Allen Lim. And when you run out of them, you hit the dreaded wall.
At a typical running ‘race pace,’ you’re burning those carbs at a rate of two to three grams (eight to 12 calories) per minute. Slower paces burn less, but even at lower intensities (eg 60 per cent of your max heart rate), you’re still only getting about 30 per cent of your energy from fat; the rest is from carbs. ‘You can still be burning two grams of carbs per minute running at lower intensities,’ explains Iñigo San Millán of the University of Colorado School of Medicine, US. That’s about
2,000 calories from carbs for a four-hour marathon.
With the right amount of carb fuel in your tank, you can perform better for longer. ‘Carb-loading doesn’t mean you’re going to be faster. It means you can push yourself further without fatigue,’ says sports dietitian and nutritionist Leslie Bonci. In fact, research shows that proper carbloading can push that wall out by about 20 per cent. And that’s something every runner wants.
• THE LATEST SCIENCE OF MAX STORAGE
Everyone loves a pre-race pasta dinner, but one carb-heavy meal is not going to cut it if you haven’t been following these best carbloading practices leading into race day. Here are the best tips to follow:
Go with grams, not percentages
This one’s especially important for women: research shows you need three to 4.5 grams of carbohydrate per 450g of body weight daily leading up to your event to achieve max glycogen capacity. Studies show that runners may not hit those numbers by following the general advice to eat about 85 per cent of their calories from carbs. In fact, researchers used to believe women couldn’t carb-load. Then they discovered they often simply weren’t eating enough, so even at 85 per cent carbs, they never reached four grams of carbs per
450g per day. Once they did, their glycogen stores were loaded and their performance improved.
The easiest approach is making the meals you’re already eating more carb-dense, says Bonci. ‘Add berries and a banana to your usual bowl of porridge, and you’ve more than doubled the carbs without having a second bowl.’
Feed your legs
You store glycogen in all your muscles, but your biceps can’t bail out your quads when they run dry. Runners especially need to stay fully loaded if they want their legs maxed out, says Olympic gold medal triathlete Gwen Jorgensen, who has recently been transitioning to longer distances on the road and track, and experimenting with the marathon. ‘In triathlon, I didn’t need as many carbs because the training stress was spread across all my muscle groups. In running, I am taking carbohydrate from my legs only, so I have to be completely fuelled.’
To ensure your legs are loaded, eat your high-carb meals after your taper-week runs, says Lim. ‘If you eat 1,000 calories of carbs and haven’t exercised, those carbs will diffuse through your muscles equally. If you eat them after you exercise, the muscles that have been contracting are more sensitive, and the carbs will preferentially go there.’
Baby your muscles
Tired, damaged muscles store less glycogen – about 24 per cent less, according to research. Taper intervals are fine, but avoid anything new or stressful during this time, says
Lim. ‘If a muscle is sore, it will do a poor job of storing glycogen. Even a deep-tissue massage, which can break apart muscle fibre, can be a bad idea if you’re not used to it.’
Give it time
Experts disagree on how long it takes to achieve maximum storage, but one night doesn’t cut it. If you train low or otherwise don’t eat a high-carb diet, give yourself about a week to 10 days, says Lim. If you typically eat a moderate- to high-carb diet, increase your carb intake to hit five grams per 450g one to two days in advance, Bonci says.
Definitely ease up on the fibre two days out, adds sports nutritionist Ilana Katz. And read your labels, especially if you eat non-grain, specifically legume-based, pastas, which can have 30 per cent fewer carbs and more than twice the fibre. ‘The day before should be skinless potatoes, bananas, pasta and other quick-burning carbs.’ You can practise on one of your long runs about a month out to see how you feel, and adjust accordingly.
Embrace the potential energy
Every one gram of glycogen stores with about three grams of water. If you taper and load correctly, you may gain four or more pounds of water weight. But don’t panic. That’s just the full tank of energy and hydration you need to power you to the finish.