Maybe your goal is to build muscle. Or maybe you’re aiming to increase your mileage. Either way, what you choose to eat and drink pre-workout can propel you to success—but the wrong choices can hinder your progress.

So before you head out to your next workout, pay close attention to what you’ve been putting on your plate in the hours leading up to it. These six diet blunders can do damage, whatever your goal. Whether you’re pounding the pavement outside or pumping weights at the gym, one thing stays constant: Your body needs the proper fuel to perform.

Carbonated Drinks:

Drinks like seltzers and sodas are infused with carbon dioxide, which creates carbonation. Those bubbles can make people feel gassy and full, or cause abdominal pain. Most of the carbonation escapes through your mouth, but some should still make it to your stomach, causing short-lived bloating and gas. It should pass within an hour.

Certain discomfort is good, like if you feel the burn completing your last couple reps or finishing a sprint. But you need a basic level of physical comfort to be able to push yourself at all. If carbonated drinks make you feel bloated or crampy during your bike ride, lift session, or run, it can keep you from reaching your full potential.

Instead, twist open a bottle of plain water to hydrate. You really only need a sugar-containing sports drink if you’re exercising long enough to deplete your carbohydrate stores. If you’re exercising for 90 minutes or longer at moderately high intensity, you can reach for a sports drink: In those cases, your body can immediately use those simple carbs from sugar for energy.

Related article: 6 Simple Tricks To Keep Your Diet On Track And Achieve Your Goals

Fibre Rich Foods:

Yes, that black bean vegetable soup is a great choice for lunch—the fiber fills you up, so you’re not hungry an hour later. But while fibre is great for your gut, it can hinder your workout. High-fibre foods—like broccoli, high-fiber cereals, or lentils and other legumes—take longer to digest and draw blood to your digestive system.

Then you have a lot of blood flowing to your gastrointestinal tract when you want it to be flowing to your muscles. This means your muscles aren’t getting the oxygen, sugar, and amino acids—all delivered by the blood—that they need during a workout.

With about 15 grams of fibre per cup, black beans can also lead to gastrointestinal distress while running, when there’s more jostling of your stomach. That can make you feel queasy and bloated, give you cramps, make you fart, and cause unwanted bathroom breaks.

If you have to stop to go to the bathroom or your stomach is in pain, that’s going to hinder your performance. Men ages 50 and younger should get about 38 grams of fiber per day, so don’t skimp on the macronutrient throughout the whole day—but do limit your intake of high-fibre foods for a few hours before working out.

Related article: 10 Tasty Keto-Friendly Vegetables That Are Incredibly Low-Carb

Low Carb, High Fibre Protein Bars:

Carbohydrates are your body’s preferred energy source. Your body converts carbs into sugars, which then get absorbed into your bloodstream, travel into the cells in your body, and can be used for energy.

A lot of strength athletes think they don’t need carbohydrates, but they do. Our muscles, our brains, they function primarily on carbohydrates. If you go low-carb, your body will break down muscle proteins for energy, which can prevent muscle growth.

During anaerobic activity, carbohydrates are the only source of energy. Without carbohydrates, there will not be enough energy for a hard workout.

So if you need a snack before your workout, try a low-fibre bar with anywhere from three to five times as many grams of carbs as protein—say, 15 to 25 grams of carbs and 5 grams of protein—within the hour. (Those high-fibre bars can spark GI distress.)

The protein in the bar is important too, since it promotes muscle maintenance and growth, and protects against muscle breakdown. If an athlete does not consume enough protein, the body will break down muscle tissue, leading to overall protein loss and a decrease in performance.

Related article: 10 Foods That Contains Highest Amount Of Protein To Add To Your Muscle Gaining Diet

Nuts:

Everyone thinks nuts are this super-food, but they’re mostly just fat. And fat, like fiber, travels more slowly through your body. That means more blood flow to your GI tract and liver when you are trying to digest fat-heavy foods.

Nuts, cheese, and avocados contain protein, which is good, but their high fat content makes them pre-workout no-nos. You don’t want to eat something high in fat, like fast foods, fried foods, or cheesy foods. Avoid them six to eight hours before your workout.

Related article: Try This Great Variation Of Nuts To Help You With Your Weight Loss Journey

Whole Grain Toast:

Complex carbs—like those in whole grains, vegetables, and beans—won’t help you fulfill your potential during endurance training. Endurance athletes are going to be better off with simple carbohydrates, which your body can absorb more rapidly for immediate use.

That’s one case where you might want to go with the plain white toast: It’s primarily made up of simple carbs and will supply your body with readily available energy. Plus, foods high in complex carbs, like brown rice, chickpeas, and sweet potatoes, are also rich in fiber, which can up the discomfort level.

Related article: Use This Healthy Grocery List For Good Health and Top Performance

Spicy Foods:

In some people, hot and spicy foods—say, dishes with jalapeño peppers or hot sauce—can trigger heartburn or acid reflux, caused by acids that escape your stomach and enter your esophagus. That leads to the uncomfortable burning sensation in your throat and sourness in your stomach, which can make your workout feel lousy.

Especially on important days—like when you’re running a 5K or trying for a PR on bench—make sure you’re avoiding foods that don’t sit well with you. Practice what you eat just like you practice all the other skills that are involved in your sport.

Not sure how you react to the heat? To help you recognise and remember which foods spark discomfort, keep a diet diary and take note of any adverse reactions after you eat.