Do I Need to Eat During My Runs?

A runner holds an energy bar and a bottle of water during the Virgin Money London Marathon on April 13, 2014 in London, England.
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Question: Do I Need to Eat During My Runs?

"I'm training for a marathon. When do I need to eat during my long runs? And what should I eat during long runs?"

Answer: You Need More Fuel After 90 Minutes of Running

When you run for under 90 minutes, most of your energy comes from stored muscle glycogen. If you're running for longer than 90 minutes, the sugar in your blood and liver glycogen become more important because your stored muscle glycogen gets depleted.

Fueling with carbs during your longer runs will prevent you from running out of energy and help boost your performance.

How Much to Fuel During a Long Run

How much do you need to eat on the run? A basic rule of thumb is that you should be taking in about 100 calories after about an hour of running and then another 100 calories every 40 to 45 minutes after that. You may need more depending on your size and speed, so make sure you carry an extra one or two gels (or other food). If you feel hungry or low on energy, you can definitely consume calories "off-schedule".

How to Fuel During a Long Run - Drinking and Eating Calories

One way to get carbs on the run is through sports drinks. They are designed to provide no only carbs but also electrolytes (salts) that you are sweating away. Both are important to replenish. The advantage of liquid calories is that you need to rehydrate anyway, and it is convenient to take in your fuel calories at the same time.

Also, you won't have to chew and risk choking while you are breathing hard from your running effort.

Energy gels are also designed for ease of use by runners, and the packets make it easy to judge how many calories you are taking in. An advantage is that you won't need to chew, but the disadvantage is that you will need water or sports drink to wash them down.

Otherwise, you have a lot of sugary residue in your mouth.

Solid foods can be tolerated, but they need to be small and easy to digest. There are numerous products on the market, such as sports gummy chews, energy bars, and even sports jelly beans, designed for long-distance runners to eat on the run. These often provide a little salt replacement as well as carbs. Experiment with what works best, especially for the amount of chewing needed and ease of use. You may also find your digestive system does better with one product or another.

Some runners prefer to eat pretzels or sugary candy such as gummy bears or candy corn. Fig newtons or other cookies could be just as good as an energy bar. These are far less expensive that the products designed and marketed for runners, and they may be just as good for fuel. Start experimenting with different foods, gels, and bars on your long runs to see what you prefer.

Source:

Cermak NM, van Loon LJ. "The use of carbohydrates during exercise as an ergogenic aid." Sports Med. 2013 Nov;43(11):1139-55. doi: 10.1007/s40279-013-0079-0.

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