Running Your First Half Marathon? Here’s What to Eat

By Leah – November 4, 2011

Most runners can make it through a 10K with a few cups of water and are at the finish line long before even beginning to think about food. But a half marathon changes the landscape. Facing 13.1 miles, most runners wonder, “Do I need to do something special so I don’t run out of energy out there?” For everyone in Austin taking on the Austin Fit Magazine Distance Challenge Series, now’s the time to consider new nutritional needs.

Though it may not feel like it on the first few long runs, we humans were meant to move. Our bodies perform well on the fuel we create from a healthy diet and staying hydrated from day to day. Typically, we consume enough water and calories to put us through the 30-90 minutes of effort required to run a 10K. The average runner in the 55,000 field at the 2011 Atlanta Peachtree 10K finished in 1:17 (that’s a 12-minute mile, or 5 miles per hour). Compare that to the much smaller and faster group at the 2010 Uptown Classic here in Austin, where the average man finished in 53 minutes and the average woman in 1:02. Average times at the 2010 Run for the Water 10-miler were 1:24 for men and 1:39 for women. Clearly, as the distances get longer, so do finishing times, with average times for the 2010 Decker Half Marathon at 1:54 for men and 2:15 for women. That’s almost twice as long on the feet as that first fast, flat 10K.

It’s the 1:30 mark that brings nutrition into play. Our bodies are designed to store approximately one-and-a-half to two hours’ worth of glycogen, the chemical our bodies derive from carbohydrates. Glycogen that is not immediately used as energy gets shuttled off to muscles and the liver, where it is stored for later use. If you have more glycogen than you can use or store, the leftovers become fat. While fat can be used as energy (primarily in long, slow exercise), your body still requires glycogen to actually fuel the process of turning that fat into energy. On the other hand, if you don’t have enough glycogen, your body can burn protein. This is detrimental as protein makes up your muscles, bones, and tissues, and this energy-producing process stresses your kidneys. So it’s very important to supplement glycogen levels while you’re exercising over time periods exceeding your body’s glycogen stores. And that means fueling on the run before you tap out your stored energy.

The type of fuel a runner takes in is very personal; what works well for one runner may send another runner screaming to the port-a-potty. Because of those individualized responses and the fact that all sports gels are not the same, it’s very important to test different sources of fuel during practice runs. What separates one brand from another may be the type of sugars used, whether or not gels contain caffeine, and the amounts of other ingredients included. It’s always a good idea to see what items will be provided on the race course and start testing with these. The Austin Marathon (full and half) will provide Lemon Lime Gatorade every mile. The 3M Half Marathon will have sports beverages at miles 4, 8, and 12, though the type has not yet been announced. Austin Runners Club puts on the Decker Half Marathon and, as a non-profit, relies completely on donations; therefore, aid station supplies will be announced when sponsors and budgets are confirmed.

Sports drinks, like gels, vary widely in their makeup. It is not necessary to use sports drinks for shorter weekday runs; staying hydrated throughout the week will see you through those shorter workouts. In fact, sports drinks can be a hidden source of unneeded calories. Many runners are surprised that they don’t lose weight during training, and the culprit is usually eating too much (“I ran a bunch of miles, so I can eat what I want to”). Running burns roughly 100 calories per mile; each gram of carbohydrates consumed equals four calories of energy. A 10K effort burns, on average, about 600-800 calories. This isn’t a completely standard amount, as each person will use a slightly different amount of calories. To figure your approximate calorie burn per mile, multiply your weight by 0.73. This formula assumes a 12-minute mile, and your mile pace may vary (and may vary greatly depending on the run you’re doing). A faster pace will burn somewhat more calories, though more fit runners burn calories at a slower rate than untrained runners. Temperature, wind, and terrain also affect rate of calorie consumption because effort level changes. In all, it takes 3,500 calories to equal one pound, and that’s a lot of running. That 32-ounce bottle of Lemon-Lime Gatorade you picked up at the convenience store on the way home after a long run is actually 4 8-ounce servings, each with 50 calories and 14 grams of carbohydrates. Each gel you ate on your run is somewhere in the 100 calorie range, so it’s quite possible that calories you ingest during a long run equal the calories you burned. Since it’s important to keep your energy stores up and not deplete them in order to finish your long run strong, the place to look for excess calories or problems with weight loss is in your post run food. Making smart food choices will go a long way towards a achieving successful race results—and a great runner’s body.

The International Association of Athletic Federations (IAAF) recommends that distance runners and race walkers take in 20-60 grams of carbohydrates per hour. What does that mean? They provide a sample chart of foods that fit the bill:

– 400-500ml of sports drink
– (13.5 fluid ounces)
– 250ml of flat soft drink
– (8.4 fluid ounces)
– 1 packet of sports gel
– a sports bar
– 1 large or 2 small bananas
– 1 thick slice of bread with jam/honey
– 35-40g of candy (a little over 1 ounce)

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