How to carb-load for marathon week

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This week, thousands of runners are focused on one thing: tackling a marathon. Whether you are in training for a late spring marathon or gearing up for next week’s London Marathon, the subject of fuelling has probably come across your mind. At this point, you’ve likely ironed out your pre-race and mid-race fueling, but you might still be wondering exactly how to carb-load in the days leading up to the big event. Here are some simple tips to keep in mind to get to the starting line properly fuelled and confident.

Things to keep in mind when thinking about carb-loading

First off, it was once thought that in order to carb-load properly, you had to severely restrict your carb intake and up your protein-fat intake in the weekdays leading up to race day, then switch to carbs two days before the race while ignoring protein and fat. Luckily, this is no longer the case, and there’s no need to restrict carb intake. Instead, begin reducing your training load while slowly increasing your carb intake. This practice of tapering plus adding fuel to those muscles basically helps you load the body’s fuel tank (muscle glycogen capacity) so that when the starting gun goes off, your muscles are fully loaded and your stomach doesn’t need to be stuffed.

To carb-load properly for the race, you will be tapering in the days and weeks beforehand. If you want to experiment in advance, you can carb-load the day before a long run, but it won’t quite be the same since you’ll only be fuelling 24 hours out, and you won’t have the benefit of rest and taper. But a practice run is not necessarily a bad idea if your schedule allows. By practicing, you’ll essentially prepare your gut for the future heavy carb load and get a preview of what the feeling of increased muscle glycogen stores may be like; carbohydrates attract water, and many athletes report that carb-loading makes them feel a bit stiffer, which is another reason why a shake-out run the day before is helpful.

Give yourself a week before race day to focus on carb-loading

You can begin carb-loading as early as five days prior by slightly increasing your carb intake and then, in the two days before the race, really start to pound those carbs. In order to not totally overwhelm yourself with calories, it’s not unusual for protein and fat to fall by the wayside during these two days. To get into the specifics, aim for a carb intake close to 3.6 to 5.5 grams per pound of body weight in those one to two days immediately before the race. When you do the math, this tends to be a whole lot of carbs, and the reason why protein and fat often get put on the back burner in the hours before the race. 

The easiest way to achieve a simple, successful carb-load is to include carbohydrate-rich foods at every meal and snack. This means bread, pasta, rice, cereal, potatoes, and fruit should be mainstays.  Simple sugars and refined grains, while usually not a large component of your diet (right?), get the green light in the days leading up to the race. These foods are quick to digest and don’t often contain the fibre which has been known to cause GI distress as the mileage piles up.

Of course, there are plenty of healthy foods that are rich in carbs and therefore no need to overdo it on “junk” carbs, especially if you have a delicate system that isn’t accustomed to that type of fuel. At the end of the day, it’s always important to live by the mantra “nothing new on race day."