No one wants to feel like they're dragging through the second half of spin class. But rather than blaming the instructor, relationship stress, or a bad night's sleep, think about what you ate before hopping on the bike. Pre-workout nutrition makes a huge difference when it comes to reaching your max potential. And the smart way to fuel up involves carbs. Think of them as energizers rather than a six-pack's enemy number one. "Carbohydrates are fuel for your muscles," says Alissa Rumsey, M.S., R.D., C.S.C.S. "Without them, your muscles cannot work as hard." They're key to keeping your body going when things get tough. A study published in the journal Applied Physiology, Nutrition, and Metabolism found that eating carbs 15 minutes before exercise helped study participants run 12.8 percent longer than when they had the placebo.
Here's how it works: Your body breaks carbohydrate molecules into glucose. Glucose then gets shipped off to the muscles, where it's converted into energy and stored until your body's energy supply runs low. Eating a high-carb meal four hours before exercising could raise glycogen levels by as much as 42 percent, according to a study published in the Journal of Applied Physiology. As you probably have guessed, though, not just any carb will do (sorry, candy bars and doughnuts). You have to find the carbs that'll keep you going strong until cool-down. Here's how to choose the good carbs to eat before a workout.
"Good" vs. "Bad" Carbs
The best exercise-boosting carbs include whole foods like whole-wheat bread, fruit, yogurt, milk, and starchy vegetables, says Rumsey. That unprocessed aspect qualifies them as "good," or unrefined. These carbs take a slow-and-steady approach to releasing energy (that's why a morning serving of oatmeal keeps you full until lunch). Refined carbs, on the other hand, are processed, which usually means they're stripped of any beneficial nutrients by the time they hit your plate. Your body quickly absorbs these refined carbs, such as white rice, cookies, and pasta made with white flour, giving you an instant energy spike.
In most cases, unrefined carbs are the way to go, and processed, refined carbs are out if you want to lose weight, but the winner isn't as clear-cut when exercise is on your agenda. Since refined carbs hit your system more quickly, they could be helpful if you need a quick boost before a workout, says Rumsey.
Pay Attention to the Clock
The type of carbs you want to eat depends on how long you've got before you plan to hit the gym. If you're a few hours out, make yourself a meal with one-quarter to one-third of your plate filled with unrefined carbs, like sweet potatoes, beans, or quinoa. If you'll be heading to the gym in an hour or less and you haven't eaten for three or four hours, it's time to load up on a carb-heavy snack with 30 to 60 grams of carbohydrates, says Rumsey. That could be half a bagel with a spoonful of peanut butter, or a bowl of cereal. (Here are a few more ideas on what to eat before a morning workout.)
Not exactly the meal-planning type? You can still fill up on your way out the door. Just reach for a snack filled with fast-digesting carbs, such as half a banana with a spoonful of peanut butter or two graham crackers with some jelly, she says. There's no need to force carbs down, though, especially if you'll just be hitting the gym for an hour or so and not embarking on an Ironman. One study published in the journal Nutrients found that while there's plenty of science supporting the benefits of eating carbs a few hours before exercise, eating them within an hour of working out hasn't been shown to boost performance (though it doesn't seem to hurt either). If your last meal was within the past four hours, you should have enough in your stomach to power through, says Rumsey.
Figure Out the Best Carbs for You
Finding out which carbs your body finds agreeable before a workout comes down to trial and error. "The choice of refined or unrefined will depend on your tolerance and how your stomach feels," says Rumsey. Digging into a bowl of oatmeal an hour or two before exercising could help one person push through to the finish, while another person might not feel like it digests quickly enough, she says.
Don't limit your carbo-loading to solid food. Sports drinks can do the trick, too. U.K. researchers asked seven athletes to ingest sports drinks with different concentrations of carbohydrates. The athletes drank 5 milliliters per kilogram of their body weight five minutes before exercising and then every 15 minutes during the workout. When they drank a solution with 6 percent carbohydrates, their endurance increased by 34 percent compared to when they drank the 10 percent concentration. Since they ran longer, they also ran about 225 meters farther. (For reference, Gatorade Thirst Quencher is right at this sweet spot of 6 percent carbohydrate concentration.)
The types of carbs you eat could also affect how hungry you are afterward, finds a study published earlier this year in the journal Appetite. After participants did an hour of brisk walking, researchers recorded their hunger levels in 30-minute intervals. They found that those who ate a meal with a glycemic index (GI) of 39 (which included a fruit drink) were less hungry at the 30-minute and 1-hour post-workout marks compared to people who had a low-GI breakfast without fructose, and compared to those who ate a high-GI breakfast. GI refers to how carb-rich foods affect your blood glucose, with high-GI foods like bagels or pretzels raising blood glucose levels more than low-GI foods like milk, lentils, nuts, and vegetables.
No matter which pre-workout carbs you go for, try adding a hit of protein, too. Rumsey says, "Carbs are the fuel, while a small amount of protein helps to prime the pump to make amino acids available for your working muscles."