Skip to main content

The Manual may earn a commission when you buy through links on our site.

Carbohydrates 101: The dos and don’ts of carb loading

Will carb loading help you meet your fitness goals?

Gluten free diet concept - selection of grains and carbohydrates for people with gluten intolerance, copy space
anaumenko / Adobe Stock

Carbohydrates are a primary energy source for our bodies and are especially important for fueling our workouts. Throughout your workout, your body utilizes carbohydrates from glycogen stores, often stored in the liver or muscles. With the idea that carbs help to fuel great workouts, many athletes have turned to a fitness and nutrition practice known as carb loading, which can help some athletes improve their athletic performance.

So, what exactly is carb loading, and how is it done? Which types of healthy carbs should you consume during carb loading? Below, we’ll break down all the answers in this carb loading guide to help you determine if carb loading is a tool to incorporate into your fitness routine. Further, we’ll note common mistakes made when carb loading to help you succeed.

a sliced loaf of bread on the counter
Mariana Kurnyk / Pexels

What is carb loading?

The concept behind carb loading starts with the idea that the body stores glycogen to be used for energy. To carb load, an athlete will consume a large portion of carbohydrates a few days before a major event or competition to load their body up with high glycogen stores. In addition to consuming more carbs than normal, carb loading also involves athletes reducing their activity levels in the days before an event. Reducing physical activity before a competition helps athletes hold onto as much glycogen as possible, hoping to improve their athletic performance.

A carb-loading strategy can be an effective approach to improve athletic capabilities, but only for athletes competing in certain types of sports or exercises. Research suggests that short-duration exercises (under 90 minutes) do not require excess carbohydrates for optimal performance. This also includes short bursts of activity (such as sprints) or weight-training exercises. On the other hand, carb loading helps to reduce fatigue and improve an athlete’s energy levels by 2 to 3% for exercises that last longer than 90 minutes.

Shot of person's feet while running
Fotorec / Pixabay

Who should and shouldn’t try carb loading?

Athletes who perform long-duration exercises over 90 minutes may benefit from carb loading. Carb loading is often used by athletes who participate in prolonged sports such as endurance cycling, swimming, and long-distance running. However, carb loading may not be the best strategy if you’re training for recreational purposes. One of the most common mistakes that can hold back your training is trying carb loading when you don’t need to. Many people falsely believe that every active athlete needs to try carb loading when this is not the case.

For most general and gym exercise sessions under 90 minutes, carb loading will not provide any benefit. Furthermore, consuming too many carbs can impair your exercise performance and lead to excess weight gain.

Man swimming backstroke
Yulia Raneva / Shutterstock

How to carb load for athletes

There are various carb-loading strategies that athletes use. Some athletes also seek guidance from nutritional experts or coaches to monitor their carb intake. The most common approach to carb loading involves consuming about 10 grams of carbs for every kilogram of body weight. Usually, this is done about two to four days before the sporting event or competition. Some athletes prefer a less aggressive, same-day carb loading technique which involves consuming about 1 to 4 grams of carbohydrates for every kilogram of body weight. Which method you choose depends on how you feel and perform best while exercising.

Many athletes also continue to consume carbohydrates during exercise as well, often in the form of electrolyte drinks with added glucose.

A brown rice-based dish with toasted bread slices served on a plate with spoon and fork.
yalamber-limbu / Unsplash

Consuming the right type of healthy carbohydrates

The types of carbs consumed also play a role in the effectiveness of a carb-loading strategy. Eating carbohydrates low on the glycemic index, such as pasta or grainy bread, may be more effective at providing energy during exercise. This is because low GI index carbs are slowly released into the bloodstream. Examples of healthy carbs to consume include whole grains from brown rice or healthy steel-cut oats.

If you’re new to carbohydrate loading, it’s best to stick to safe foods that do not cause your stomach upset. Trying new foods that you do not regularly consume or foods too high in fat can cause digestive symptoms and impact your performance. Carbs to avoid when carb loading before an athletic event include things like ice cream, pizza, donuts, or any other processed carb that is also high in fat content.

Pasta carbonara
Rob Wicks / Unsplash

Should you try carb loading?

Carb loading is a science-backed approach that can help you achieve your fitness goals if competing in long-duration exercise over 90 minutes. If you’re training just to improve your physical fitness, consuming a standard amount of carbohydrates is a better strategy to help you maintain a healthy body weight and exercise at your best.

Emily Caldwell
Emily is a freelance writer with a special focus on health, fitness, lifestyle, food, and nutrition topics. She holds a B.S…
Don’t make these common mistakes with your running gear in winter
Stay safe when running this winter
A man and woman running on a snowy winter road

As winter sets in and temperatures begin to plummet, many dedicated runners refuse to let the chill keep them inside. If you prefer to run outside rather than on the treadmill, you don’t need to let the cold weather stop you. Winter running can be invigorating, but it’s important to make sure you’re prepared before you hit the pavement. The proper running gear is essential for protecting yourself against the cold, wind, and possible rain and snow.

Many people actually dress too warm when heading out on a cold-weather run and end up being uncomfortable. It’s recommended you dress for weather that is 10 to 15 degrees warmer than the actual temperature when getting ready to run outside. This allows your body to adjust to the temperature without overheating. Here’s an overview of what you should wear when running outside in the wintertime.

Read more
4 delicious crock pot recipes: These low-carb, keto-friendly soups are perfect for winter
Warm up with these incredible keto recipes
Carrot soup

As we dive into the holiday season, carb-heavy foods seem to be everywhere we go. Foods high in carbs and sugars are certainly delicious, but they can leave us feeling sluggish. During the busy holiday season, the last thing we need to feel is slowed down -- we have shopping and gift wrapping to do! That's why swapping heavy-carb meals with simple, low-carb foods is a great idea to keep you energetic this winter. Even better, cooking low-carb recipes in a slow cooker can help save you time so you can focus on spending time on the holiday activities you love most.

Craving a delicious winter soup? These four crock pot recipes are perfect for your low-carb diet and are sure to hit the spot in the cool weather. The low-carb meals are also keto recipes, making them an excellent choice for anyone -- including those on a low-carb, ketogenic, or diabetic diet. Warm and delicious, you're bound to add these favorites to your go-to list after a few tries.

Read more
Spaghetti squash: Your new favorite low-carb fall vegetable swap
You might have the wrong idea about spaghetti squash — let us help
Spaghetti squash in a pile

Named spaghetti squash for its spaghetti-like texture, spaghetti squash is a vegetable that offers tons of health benefits, yet many people often forget about it. As you walk through the grocery store, do you tend to gravitate toward the same vegetables every time?

Veggies such as broccoli or spinach are "go-to" vegetables for many shoppers, especially since they require minimal effort to cook. But don't shy away from cooking spaghetti squash -- a veggie that is simple to cook, that tastes delicious, and is high in nutrients.

Read more