Runners have long practised the art of carbo-loading. In fact, we practically invented it. But, it might surprise you to learn that not all carbohydrates are created equal.
"Runners used to just be concerned with taking in enough carbs,"says Lisa Dorfman, a sports nutritionist. "Now we're taking it a step further and looking at which carbohydrates are best for us."These days runners aren't the only ones taking a closer look at the kinds of carbohydrates they're eating.
America's dietary guidelines specify not just how many servings of carbohydrates you should be eating every day, but also what type of carbs each serving should consist of.
The guidelines recommend an average of 150g of carbohydrate per day (based on a 2,000kcal-per-day diet) and call for half of that – or at least 75g – to be consumed as whole grains. Research showed that the average person was only eating about one serving a day of whole grains. The popularity of very low-carbohydrate diets may have played a role in the public's move away from healthy whole-grain foods.
"The way you can judge how healthy a carbohydrate food is, is to look at the amount of fibre it has,"says Dr Arthur Agatston, author of The South Beach Diet. "The more fibre, the more slowly it'll be digested, the more nutrient-dense the food will be, and the better it is for your heart, your cholesterol, and your overall health."
So whole-grain foods, which are full of fibre, should be regular staples in your daily diet. Whole grains are those where the entire grain including the bran, the germ, and the endosperm is whole. It's within the whole grain that you find nutritious B-vitamins, iron, magnesium, selenium, and fibre. When whole grains are milled into refined grains, the bran and the germ – and the nutrients they contain – are lost. Lots of refined carbohydrates are fortified to add back some of the nutrients, but you can't add back all the fibre.
Runners, of course, need more than the average amount of carbohydrates, especially leading up to a marathon or other endurance race. Carbohydrates are, after all, the top choice for fuel and the best energy source. "Runners should be taking in about 55 to 65 per cent of their calories in the form of carbohydrates,"says RW Nutrition Editor Anita Bean.
The fitness runner will do fine at the lower end of this range, while high-mileage runners need close to 65 per cent of their calories as carbohydrate. While no nutritionist will advocate large amounts of biscuits or other refined carbohydrates, the good news for runners is that all carbs can play a role in a healthy diet. It would be wrong to classify carbs as "good"or "bad,"it's just that whole grains have more fibre so they take longer to break down, while refined or processed grains have little fibre and are quickly and easily broken down and used for energy. That means both types of carbs serve a purpose.
Before a long race or run, you want to take in carbs such as whole grains and whole fruits because they will offer slow-burning energy. "It's almost as if you're running with a drip in your arm, slowly letting sugar into your blood stream,"says Agatston. "If you have frosted cornflakes for breakfast before a long run instead of porridge, your blood sugar shoots up, then down, and you don't have a reservoir of energy."
During a long run – when your energy stores are running low – it's time to consume some fast-acting carbohydrates that will convert immediately into glucose and keep you from hitting the wall. Reach for a white-flour bagel, sweets such as jellybeans, or sports gels or drinks. For replenishing your carb stores after a run – you want to restock your glycogen stores within an hour of crossing the finish line – opt for a mix of slow- and fast-burning carbs, such as a whole-wheat bagel and a banana.
Of course, eating the right balance of the different types of carbohydrates recommended in the new American dietary guidelines means you have to be able to identify the types of carbs you're eating. In other words, you have to read labels.
"Brown isn't always a foolproof indication of something being whole grain,"says Dorfman. Instead of just relying on the colour or even the name, read the fine print on the nutrition label. Take bread, for example: the first ingredient should be a whole grain – like cracked wheat or wheat flour, and it should have three to five grams of fibre per serving.
Products that list simple sugars – such as high-fructose corn syrup – near the top of the ingredients will not offer the slow-burning energy of a whole-grain, unprocessed food.
The bottom line is to seek balance. "For runners, there's no reason not to eat some refined carbohydrates as long as you make sure to take plenty of whole grain carbs, too,"says Agatston. "Eat lots of fruit, vegetables, and whole grains, and you'll have a nutrient-rich diet that'll keep you running well."