Sunny Blende, a sports nutritionist, once described ultramarathons as “eating and drinking contests, with a little exercise and scenery thrown in.”
Marathons, too, have come to resemble mobile buffets, with fueling stations almost every mile. And top cyclists and triathletes are now scarfing down more sugary drinks and gels than ever in search of a performance edge. It’s enough to make some casual athletes wonder whether they should pack some calories every time they lace up their trainers or head to the gym.
This growing focus on mid-exercise refueling is based in part on research showing that elite athletes can digest calories more rapidly than previously thought. But whether the rest of us should emulate this approach is less clear, according to running coach and sports nutritionist Matt Fitzgerald. In fact, he said, “the topic raises fundamental questions about the purpose of fueling in training.”
Before you rethink your workout nutrition plan, Mr. Fitzgerald and other experts recommend considering three key variables: how long you’re exercising, how hard you’re pushing and what your goals are.
How long is your workout?
The case for refueling during a multihour effort like a marathon is straightforward. Your body can store only a limited amount of carbohydrates, the fuel of choice for hard exercise. After 90 to 120 minutes, unless you replenish your body’s stores of carbs, your muscles will shift to using forms of fuel that aren’t as easily metabolized, such as fat. That causes the heavy-legged and lightheaded feeling endurance athletes refer to as “bonking,” or hitting the wall.
Even for efforts shorter than 90 minutes, extra carbs can be helpful. Unlike a car that can drive at full speed until it runs out of gas, your muscles start working less efficiently even when they’re halfway fueled, said Tom Shaw, a performance nutritionist who has worked with professional soccer clubs in Europe and the Middle East.
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Do You Really Need to ‘Refuel’ During Exercise?
