I remember the first time I “hit the wall.” It happened in the 9th mile of a 10-mile training run for my first half marathon. At the time, I was a brand new runner, and that run was only my second 10-miler, ever. In glorious newbie fashion, I had been training with no understanding of the proper runner’s diet. I’d scaled way back in my caloric intake on a diet that focused on lean protein, and adopted the habit of drinking close to a gallon of water a day, all while increasing my mileage to 23+ miles per week.
That morning, I set out on my 10-mile course along hilly country roads. I felt strong and confident, until the last two miles. Sudden fatigue overtook me. My legs turned to cement; lifting them became a struggle with each stride. My pace ground to a pathetic limp-like gallop. I didn’t think I could finish. What was going on?
Now I know: Due to the high levels of proteins and near absence of carbohydrates in my diet, the glycogen stores in my muscles were low going into the run. Even when topped off, a person only has an average of 90 minutes worth of glycogen-fueled energy. Once my glycogen stores had depleted, my body switched to burning fat for energy. Great, right, ladies?
Your body burns energy when converting fat to fuel. When some of the energy your body was using to fuel your run is diverted for fat-converting duty, you experience immediate and miserable fatigue. That’s what happened to me. That’s called “hitting the wall.”
Having learned the lesson the hard way, I’m now wrapping up my months of preparation for Sunday’s AthHalf marathon with two days of carb loading. The goal is to saturate the glycogen stores in my muscles while resting my body, so that I have maximum, lasting energy for race day. (I’ve been training using Gu gel packs to replenish those stores as my body burns glycogen.)
So on Friday and Saturday, 85-95% of my caloric intake will come from complex and simple carbohydrates. It’s important to not increase the number of calories you take in during the carb-loading phase, rather to choose carb-intensive foods in place of others. Also, don’t indulge in heavy sauces or other high fat ingredients, as these may lead to digestive issues you do not want to deal with during a 13 mile race.
Here is a sample menu of a carb loading day, published in an article by Dimity McDowell for RunnersWorld.com. (Read the whole article HERE.)
A day of carbo-loading for a 150-pound runner
1 bagel with 2 tablespoons strawberry jam (71 g)
1 medium banana (27 g)
8 ounces fruit yogurt (41 g)
8 ounces orange juice (26 g)
2 Nature Valley Oats ‘n Honey
Granola Bars (29 g)
8 ounces Gatorade (14 g)
1 large baked potato with 1/4 cup salsa (69 g)
1 sourdough roll (40 g)
8 ounces chocolate milk (26 g)
1 large oatmeal cookie (56 g)
1 Clif Bar (42 g)
8 ounces Gatorade (14 g)
1 chicken burrito with rice, corn salsa, and black beans (105 g)
1 2-ounce bag Swedish Fish (51 g)
CARB TOTAL 611 g
Since I weigh in at 130 lbs, I will adjust the amounts in menus like this. The calculation generally used recommends eating about four grams of carbs for every pound of body weight. The article mentioned above suggests using the calculator at http://endurancecalculator.com/ for a more specific number of carbs to eat based on variables including age, resting heart rate, VO2 max, and predicted finishing time.
What’s your favorite carbohydrate-loading meal to eat pre-race? I’d love to try it out!