No, carbo-loading is not an excuse to stuff your face with that bacon cheeseburger pizza. It’s not a license to pig out before your first “real” athletic run event, either. When serious endurance athletes—think marathon runners, cyclists, swimmers, and triathletes are gearing up for a race, the preparations usually involve carbo-loading in the days leading up for the event. If you’re just getting into sports like these, learn how to do it the right way so you don’t end up feeling heavy, sluggish, and even gaining more weight than when you started.

Our bodies use existing energy stores for fuel. Every time we breathe, move, exert effort, and engage in athletic events, we use the fuel stores to keep going. However, when we engage in sports that need endurance, we need the extra energy to keep up our exertion. Carbo-loading is an eating strategy involving changing up your nutrition to maximize glycogen stores (in other words, carbohydrates) before prolonged endurance activity. According to the Australian Sports Commission, carbo-loading the right way improves muscle endurance by 2 to 3 percent, allowing athletes to stay at their optimal pace for a longer time. However, there’s a thin line between carbo-loading effectively and just plain eating too much. We’ve debunked the top three myths for you here.

Myth 1: Load up on carbs before any kind of exercise.

According to experts, carbo-loading is good for long distance events—anything over 90 minutes. For anything less than that, you don’t need to carbo load. There’s no point. If, for example, you’re going on your first 10-K run, there’s no need for it.

Myth 2: You get to eat more carbs on top of your usual food intake.

Adjust proportions and the composition of your meals without increasing caloric intake. If you normally exist on 2,500 calories a day, keep it at the same amount but change where you get your calories from. If you’re eating more carbs, lessen your protein intake. According to the Mayo Clinic in the US, the amount of carbohydrates you need depends on your total calorie goal as well as your sport. For most athletes, 5 to 7 grams of carbohydrate per kilogram of weight daily is right for general training. However, endurance athletes may need 6 to 10 grams per kilogram. (1 kilogram equals 2.2 pounds.)

Myth 3: Carbo-load the day before a big event.

According to our experts, the number one mistake newbie athletes make when gearing up for an endurance event is overloading on carbs the day before. In fact, proper carbo loading begins about a week before an event. The goal is to give your body enough energy for performing well in an event without leaving you feeling heavy. It’s a process that begins with depleting your carbohydrate storage and building it up to the day of the race so it’s available for your body to burn.

Myth 4: If I don’t carbo-load, I’ll pass out mid-event.

If you typically eat a balanced diet and have been training properly and regularly, carbo-loading is not an S.O.P. If you feel like you don’t need the extra glycogen boost (especially if you’re not trying to beat a certain time or run a full triathlon event), then there’s no need to carbo-load.

Try this approach:

7 Days Before:

Adjust your carbohydrate intake to about 55 percent of your total calories per day while training at your normal level to deplete carbohydrate stores and leave enough space for the loading in the days before the race.

3-4 days before:

Increase your carb intake to about 70 percent of your daily calories. Cut back on food higher in fat to compensate for richer carbohydrates, and scale back the intensity of your training to avoid using the energy you’re loading up on.

Trisha Bautista is a freelance writer, food and product stylist, social media manager, and violin teacher. She was formerly editorial assistant and social media editor for Women’s Health Philippines, and the assistant lifestyle editor and social media editor for Cosmopolitan Philippines. She enjoys discovering easy recipe hacks, working out by herself and trying out DIY workout programs, traveling outdoors, and enjoying wine and whiskey.