May 24 2018
A registered dietitian drank beetroot juice for a week before running a half marathon to gauge how the nutrient-rich fuel would affect her.
Nutrition is a critical component to racing—duh. It’s important to remember, what works for you may be different than your running BFF. You may also note your husband can eat anything pre-race and be fine—it’s true that women’s gastrointestinal
(GI) tracts tend to be more sensitive than men’s. At the same time, there are some basic ground rules for proper fueling. Here’s how to eat right to race well—and why it’s crucial to experiment to see what’s best for you.
Regardless of your favored racing distance, how you eat on a day-to-day basis will ultimately affect how you feel during the big event. Aim for a well-balanced diet containing complex carbohydrates, lean protein and healthy fats. Drink enough water to stay hydrated too. Not sure what that looks like? If your urine is light yellow, you’re doing it right. Any darker, and you’ll want to hit the bottle.
There are two primary sources of energy expended while running: carbohydrates and stored fat. What percent you use of each depends on your intensity.
The lower effort you expend (the slower you run), the fewer calories you burn per minute and the lower percentage of carbs you use. At a higher effort (faster pace), you’ll burn more calories and use more carbs than fat. Fat is stored in abundance and provides more than twice the energy that carbohydrates do. While carbohydrates are stored in limited supply, they are more readily available, especially those consumed during exercise.
All of this is to say: If you don’t consume carbs during a race, your performance will likely suffer. This can be tricky, however, as it’s difficult for your body to digest on the run. Most women can successfully tolerate 25–45g of carbs per hour (at most 60–70g). This is a case where everyone is different and every fueling plan should be trialed before race day.
No matter what distance you choose to race, it’s important to ensure your carbohydrate stores are sufficiently topped off to provide you with readily accessible energy. In general, the longer you have until race time, the more you can eat and vice versa. About 3–4 hours beforehand, consume a healthy and familiar meal containing mostly complex carbohydrates like:
Since many races start very early in the morning, it may not be possible to consume a meal so long before the gun goes off. If this is the case, be sure you have a healthy, balanced dinner the night before like salmon, sweet potatoes and green beans. If you’re able to, about 1–2 hours before the event, consume a light snack with about 2 cups of fluid. Some people experience a drop in blood sugar (hypoglycemia) at race time with this strategy, so be sure to test it out in training first. If you’ve experienced hypoglycemia, skip the pre-race meal and drink about 7–10 ounces of your favorite carbohydrate-containing, full-strength sports drink (or something like a gel and water) about 10–20 minutes before starting.
If you’ll be running a 5K or 10K in under 60 minutes…just run. Unless you’re thirsty, there’s no need for extra fluids or carbs in a shorter race.
If a 10K will take you longer than 60 minutes or you’re doing a half marathon…fuel with a carbohydrate-containing sports drink. Continue to sip on it at regular 10–20 minute intervals throughout the race. If you don’t like sports drinks, you can achieve the same effect with water and supplemental carbohydrates (bananas or dates) and electrolytes (like SaltSticks)—or you can use sports-specific gels or chews, which deliver both. While it’s not necessary to have carbohydrates in events shorter than 1 hour, there could be a performance benefit.
If you’re running a marathon…it’s critical to have a specific hydration and fueling plan going in. Marathoners, especially 5-plus-hour female runners, are at higher risk of hyponatremia, or water intoxication. In other words, the electrolytes in your blood get overly diluted from drinking only water (or too much of it) and the consequences are very serious—sometimes deadly. Symptoms are sloshy stomach, bloating, headache, confusion, vomiting and muscle weakness. Be sure to avoid drinking too much before the race and drink at regular intervals using a full-strength sports drink during the event.
While hyponatremia is very serious, it occurs rarely. More commonly, marathoners will experience dehydration. Keep in mind that sweating is your body’s cooling mechanism and everyone’s sweat is unique. Consume 12–28 ounces of fluid per hour during the event. The hotter it is on race day, the more you’ll need. Drinking icy-cold fluids before and during the event helps manage body temperature.
If you sweat excessively, or have trouble with cramping, runner’s trots, nausea or dizziness, you may need a more personalized solution. Sweat testing is a painless procedure per-formed by a sports nutritionist where your total fluid and electrolyte loss is measured using skin patches that absorb your sweat. This allows a professional to develop a customized hydration plan for you—that you still should practice, of course.
Beyond dehydration, the other major issue for marathoners is “bonking,” or depleting your stored carbohydrates. This generally occurs after about 2–3 hours of racing, and results in a marked performance decrease. Consuming about 25–45g or more of carbohydrates at regular intervals in the form of sports drinks, gels, chews, dried fruit, crackers or energy bars will help avoid this.
Once you’re finished, if you’re going to continue to run in the following days, you’ll need to replace lost fluid, electrolytes and carbohydrates stores. Drink 2–3 cups of your favorite sports drink, soda or chocolate milk for every pound of body weight lost. Or go for water and carbohydrate- and electrolyte-rich foods like bananas, pretzels, oranges slices or potato chips.
Chris Newport is a registered dietitian, sports nutritionist, coach, exercise physiologist, mom and real-food advocate. Get your free hydration guide online at TheEnduranceEdge.com. Find her on Twitter @CoachChris_RD or Facebook at TheEnduranceEdge.