The 4 Worst Foods to Eat Before a Workout (and What to Eat Instead)

When you exercise on an empty stomach, you might not have enough energy to perform at your peak. But eating the wrong foods before a workout may sabotage your sweat session too.

We enlisted the expertise of Pam Bruzina, PhD, director of nutritional sciences graduate studies at the University of Missouri, to help you avoid the potential pitfalls of pre-workout foods.

From making you sluggish to gassy, the following foods will not set you up for success whether you're pounding the pavement or lifting in the weight room.

Skip the steak before you hit the gym.

While high-protein foods can satiate your stomach and stave off hunger, getting too much of the macro can mean sluggish digestion. Plus, eating protein-only foods means you'll miss out on the energy-rich carbs that really power you through tough workouts, Bruzina says.

Not to mention, exercising when food is still jostling in your stomach can cause major discomfort. Just think: A tummy stuffed with protein can make you feel heavy and weigh you down.

You should have a bit of protein — aim for just 10 to 20 grams — coupled with a healthy source of carbs for sustained energy.

Or think of it this way: Your meal or snack should contain at least 75 percent of total calories coming from carbs and no more than 25 percent coming from protein, Jim White, RD and owner of Jim White Fitness and Nutrition Studios, previously told LIVESTRONG.com.

Like protein, fatty foods take a long time to digest, Bruzina says.

That means they stick around your stomach for hours. And while your body's busy digesting, more blood flows to your GI tract to aid the process, so there's less oxygen going to your muscles.

In other words, your muscles don't get the stuff they need to perform their best.

The takeaway: Before you exercise, steer clear of greasy burgers and pizza as well as too many healthy fats like nuts and avocado.

From legumes to whole grains and veggies, fiber-filled foods benefit your heart, help with weight loss and are good for your gut. But a big bowl of black bean soup for lunch may hinder your workout later in the day.

Indeed, high fiber foods may cause gastrointestinal discomfort, resulting in gas, bloating or cramps, Bruzina says.

Be especially aware of fiber-rich cruciferous veggies. Nothing brings on the belly bloat like broccoli, Brussels sprouts and bok choy.

Like beans, veggies from the cruciferous family contain an indigestible sugar called raffinose, which feeds the bacteria in your colon that produces methane gas.

All this to say, you can't focus on the gym if your stomach is swollen with gas and you're booking it to the bathroom every few minutes.

But don't stop eating nutritious fibrous foods — getting enough daily fiber is essential for overall health (women should aim for 25 grams per day and men, 38 grams, per the Academy of Nutrition and Dietetics). Simply limit your intake for a few hours prior to exercise.

Love food with a kick? You might need to scrap the Sriracha sauce and postpone the jalapeno peppers until post-workout.

For some individuals, spicy foods can cause problems like gastrointestinal distress, heartburn or acid reflux during exercise, Bruzina says. Dealing with a burning sensation in your throat or an upset stomach is the last thing you need when you're exercising.

Alternatively, eating certain foods prior to a workout can offer the optimal oomph you need to push through a rough routine and improve your performance.

Specifically, complex or simple carbohydrates supply the energy required for exercise that's high-intensity and/or endurance-based, Bruzina says.

Keep in mind: Simple carbs burn faster, so they're more readily available to your body for a quick energy boost while complex carbs digest more gradually to provide a slower, steady stream of glucose, according to the American Heart Association.

For a carb-rich snack, Bruzina recommends noshing on a bagel, a slice of bread or granola bar 30 to 60 minutes before a workout. When it comes to larger meals, try munching on cereal, cooked grains or pasta four hours prior to exercising to allow for proper digestion.