Everyone gets it: To run long, you need fuel. Lots of fuel. That’s why we have carbohydrate loading. It’s the best way to make sure your tank is full.
It also explains why I see so many runners on marathon start lines looking as if they are ready for a transcontinental trek. They’re wrapped in fuel belts, backpacks, straps, and holsters brimming with every imaginable high-energy food. And quite a few I’d rather not imagine.
However, long-run fueling doesn’t have to be so complex. The human body has a simple, if limited, process by which it stores and then parcels out all the energy needed for endurance efforts. There are a few key steps you need to get right. Beyond those you won’t gain anything by attempting to haul a spare gas tank along with you.
The body’s primary energy source is glycogen—stored glucose (a type of sugar). About 80 percent of your stored glucose is packed in the muscles, and thus readily available when you are running. Since you train regularly, your muscles have become quite efficient at storing and using this glycogen.
Carbohydrate loading can also increase your glycogen supply, which explains the popularity of pasta parties the evening before most big marathons. Rice, potatoes, and breads are other simple and excellent sources of carbohydrates.
A little more than 10 percent of your body’s glycogen is stored in the liver, which becomes rapidly depleted between meals, and overnight while you sleep. For that reason nutritionists always advise marathoners to wake up early enough for a modest breakfast. In the long run, every little bit of glycogen helps.
Finally, your bloodstream contains a small amount of circulating glucose. There’s not enough glucose to supply much muscle power, but the brain demands carbohydrates around the clock. As I have emphasized at several points in this book: No runner should ever underestimate the importance of a high-functioning brain. Especially in a marathon.
Sports drinks, energy bars, and various gels don’t contain enough sugar to do much good. Carry a small supply if you like, but don’t overburden yourself (with either excess weight or worry), and don’t neglect the more important prerace glycogen basics.
Skip the carbohydrate-depletion phase: When Scandinavian researchers first explored carbohydrate loading in the late 1960s, they put athletes through a terrible ordeal: a “depletion” phase before the loading. This meant that marathoners ran a hard 20-miler a week before their event, and followed this fatiguing workout with three days of a low-carb diet. This left their glycogen supply on empty. The marathoners switched to carbo-loading only in the final three days before the marathon to top off their glycogen tanks for maximal marathon performance.
This degree of depletion proved physically and mentally debilitating. Before a marathon you want to feel strong, eager, and confident. Runners who attempted to deplete felt the opposite: weak, confused, depressed. Yes, they snapped out of it once they began consuming carbs again. But it was a tough road to follow.
Fortunately, researchers eventually discovered an easier way. You don’t need to go through the depletion phase. You’ll perform just as well—and feel a whole lot better—if you simply reduce your mileage before a marathon while simultaneously switching to high-carb foods the last two to three days.
Don’t overdo it: While Frank Shorter was winning the Olympic marathon in 1972, the American TV audience got its first lesson in carbohydrate loading. The ABC broadcast depicted Shorter’s supposed breakfast—a stack of pancakes about two feet high.
I suppose this made the point, but it grossly exaggerated the quantity. To carbohydrate load, you do not have to eat like a starving pig at a trough—not at breakfast, dinner, or any of your meals. In fact, don’t eat more than normal. Just reduce fats and proteins (and bulky, high-volume meals like salads), and concentrate on high-carb foods. When in doubt, eat an extra piece of bread or toast.
Eat a modest pre-marathon breakfast: Keep it small and simple. Have a bagel, or more of that bread or toast, spread with jam or honey if you have a sweet tooth. Wash it down with water or a favorite sports drink. Many runners find that a banana works well. Some like oatmeal. Don’t eat or drink anything that you haven’t used many times in the past. Less is more. Eat modestly. Nothing new.