Weighing the Pros and Cons
Proper nutrition fuels our exercise sessions and helps our bodies recover and make adaptations from those workouts. But the million-dollar question has always been whether or not you should eat before a workout, and if you should, of what that meal or snack should consist. This is a hot-button topic; those who work out on an empty stomach swear by it, and those who eat before exercise swear they couldn’t do it any other way. The bottom line is, after honestly assessing the types of workouts you plan on attacking, you have to figure out what works for you. Here is some helpful information to fuel your fueling decision.
Working Out on an Empty Stomach
An empty stomach is defined by the Food and Drug Administration as two hours following a meal, even though your stomach likely won’t be completely empty. For most people, unless you have blood sugar issues, it is totally fine to work out on an empty stomach, especially if your workout is going to be one hour or less, and of a moderate intensity. So, before you carb-load, be honest with yourself about whether or not your daily exercise session will be intense enough to warrant that fuel; think between 70% and 85% of your maximum heart rate for that hour. Those carbs are broken down into glucose, which feeds your muscles cells and gives you energy to go at maximum capacity. But, if you don’t burn off those carbohydrates, they’ll later be stored as fat.
“If your workout is only going to be 45 minutes, you just don’t need a ton of carbs to get you through,” says nutritionist Jennifer Gargiulo, RDN, CSSD, who stresses that it is counterproductive to guzzle a sugar-laden sports drink during a 30-minute bout on the elliptical when, in a properly hydrated individual, drinking water isn’t even really necessary during a workout of that duration. “But,” Gargiulo says, “if your kid has a two-hour soccer practice, a snack might be a good idea.”
Working Out in a Fasted State
When our grandparents were children, it was so common to go 12 to 14 hours without eating that there wasn’t even a name for that sort of schedule. But in today’s constantly-fed society, eating during a smaller window of time during the day is known as “intermittent fasting” or “time-restricted eating.” When you fast for at least 12 hours, your insulin levels drop, which forces the body to mobilize stored body fat from your fat cells to burn for energy to fuel your brain and muscles. Simply put, you can only burn stored fat when in the fasted state, and you can only store more fat when you’re in a fed state. If you want to try working out in a “fasted state,” this is easiest done if your workout is in the morning, 12 hours after finishing your dinner the night before. When insulin levels drop, glucose is no longer being taken from the blood into the cells for energy, so your body will need to turn to fat to fuel your workout. Some studies have shown fasted exercise burns up to 20% more fat than exercising after a more recent meal.
Working Out After Having a Snack
If you have not adjusted to working out on an empty stomach, an intense workout might make you feel dizzy, light-headed, nauseous or lethargic. Or, not eating might just not work for you. But the polar opposite – downing a meal or snack moments before you hit the treadmill – probably won’t work, either. Gargiulo suggests eating one to three hours before your workout so you’re not still digesting when you start your run. “Work backwards from the time you know you’ll be hitting the gym,” she says. “If you lunch is at noon and you’re working out at 3, your regular lunch should carry you through. If your workout is at 5 and you want and can tolerate a meal closer to gym-time, a snack at 3:30 is fine.”
If You’re Going to Eat Pre-Workout, What Should You Eat?
“It’s about the tolerance of your GI tract and the amount of time you have,” says Gargiulo, who recommends a light-carb based meal that also has a little protein, like a yogurt with fruit or nuts, an apple with peanut butter or a protein shake. “However, if it’s half and hour before you work out and you don’t want something jiggling around, just go with a banana or an apple sauce pack.” Gargiulo suggests staying away from too much fiber or fat, and that protein-heavy snacks should be eaten at least an hour or two before your workout.