Should You Eat and Drink During Exercise?
How to determine if, when and how you should fuel and hydrate in motion.
David Nieman ran his first marathon in the 1970s, when dreadlocks rivaled ponytails and granola hadn’t given way to Gatorade. “The fact that during exercise you’re supposed to drink sugar water and that helps you – at first we just scoffed and said, ‘That doesn’t sound right,'” says Nieman, a professor at Appalachian State University and director of the Human Performance Lab at the North Carolina Research Campus who’s run 57 marathons since.
Today, the pendulum has swung the other way. Sugary sports drinks, bars, gels, chews – you name it – are mainstream among marathon runners and mall walkers alike. One market research report estimated that the global sports nutrition industry could exceed $45 billion by 2022. Group fitness class participants are washing down energy bars with squeezable applesauce packets, and kids are showered with sports drinks and cookies after short soccer games, observes Jessica Crandall, a registered dietitian in Denver and spokesperson for the Academy of Nutrition and Dietetics. “We don’t need all of that,” she says.
But there is a happy medium. After all, some athletes (professional or recreational), weekend warriors and even gym rats need to fuel in motion to support their performance, improve their recovery and even protect their immune system, Nieman says. Here’s what to ask yourself to figure out if, when and what advice about eating during exercise applies to you:
1. What’s my goal?
If, like most Americans, you’re trying to lose weight, finding enjoyable, sustainable ways to move should take priority over finding the best snack to pack in your gym bag. In fact, one study out of the American Marketing Association even found that foods with packaging that promotes fitness – think Clif bars and Wheaties – can actually discourage people from exercising, perhaps because eaters feel like they can check their “did something healthy today” box. (Reminder: Eating a “fitness food” isn’t the same as going to the gym.)
“In a nation where … 7 out of 10 adults are overweight or obese, the last thing they should be thinking about is taking in calories while they’re exercising,” Nieman says. “You’re negating a lot of the good of that exercise bout.”
2. How long am I exercising?
If you’re, say, playing tennis for 45 minutes or jogging for 30, leave the gels at home. But if you’re running a half-marathon or doubling up on workout classes, plan to nutritionally recharge around 45 minutes in, Crandall recommends, even though you probably won’t feel hungry since your blood will be shuttled away from your digestive tract. After about 90 minutes of high-intensity exercise, the stored carbohydrates your body’s been powered by will run dry, Nieman says. “If you don’t do something about it,” he says, “exercise becomes more labored, you become more inflamed, you have more oxidative stress, you slow down and recovery is more painful.” No thank you.
3. What type of exercise am I doing?
A two-hour road race isn’t the same as logging two hours lifting weights at the gym (but flirting, stretching and showering during one of them). If you’re continuously working hard enough to make singing, but not talking, a struggle, the 90-minute refuel rule applies, Nieman says. “If you’re in the weight room and you’re really serious and you’re putting in a couple hours or more, then having a banana or Gatorade is definitely going to help,” he says. Same goes for lengthy basketball, soccer or other intense sports practices or games.
4. What should I eat?
That’s Nieman’s lab’s central question. In a 2012 study, he and colleagues compared how seasoned cyclists fared when given bananas and water versus a sports drink during two 75-kilometer rides. They found both options worked equally well performance-wise, but the banana excelled in other areas, too. “In that banana are other compounds that can benefit the athlete,” including fiber, potassium and vitamins and vitamin B6. In more recent research, Nieman’s team has found that eating bananas during exercise boosts dopamine in athletes’ blood, which acts like ibuprofen to combat inflammation.
[See: 9 Foods Packed With Potassium.]
Other research has shown the power of other fruits and fruit juices like dates, beets and watermelon – all of which contain different phytochemicals, or plant nutrients, that support exercisers in different ways – for athletes in motion. “I don’t think you can get much better than fruit,” Nieman says. Aim for 15 to 30 grams of carbohydrates (that’s a half a banana to a full banana) every 45 minutes to an hour, Crandall recommends.
Add them to your workout routine for expert results.
5. What about hydration?
A general rule of thumb is to drink 8 to 10 ounces of fluid before a long workout or race and about 4 ounces every 15 minutes during the event, Crandall says. To personalize that recommendation further, weigh yourself (naked), work out for 30 minutes (clothed) and then weigh yourself (naked) again. Double the amount you lost in kilograms to find how many liters you sweat per hour, says Brendon McDermott, associate professor of the Graduate Athletic Training Program at the University of Arkansas who chaired the National Athletic Trainers’ Association’s position statement on the topic. While most people sweat 0.5 to 1 liters per hour, if you drip much more or less than that, drink more or less accordingly. “The goal is to individualize it,” McDermott says.
6. What works for me?
Knowing yourself is more important than knowing the latest fueling and hydrating research. Keep tabs, for example, on your thirst, weight, urination frequency and urine color in the days prior to your long workout, McDermott says. If any three of them are off – say, you’re not thirsty, you’re peeing more often and your urine is pretty clear – adjust (in this case, reduce) your fluid intake accordingly. As for fuel, experiment with different products and combinations – maybe water and a half a banana one day and a sports drink with potassium and sodium the next – to see what settles in your stomach and fuels you best. “The worst thing people can do,” McDermott says, “is try something new on race day.”