Why do runners eat pasta the night before? The science of carb-loading

October 8, 2025 •

3 min read

According to sports dietitians, eating a large, carb-heavy meal like pasta the night before a race is a nutritional strategy called 'carb-loading,' designed to maximize glycogen stores for endurance events. This pre-race ritual is not a myth but a science-backed method to ensure you have enough fuel to perform at your best.

Quick Summary

Runners eat pasta before a race to replenish and maximize their muscle glycogen stores, which serve as the primary fuel source for high-intensity, long-duration exercise. Proper carb-loading is a multi-day strategy involving specific food choices, not just one large meal.

Key Points

Glycogen Stores: Carbohydrates from pasta are converted into glycogen, the body's primary fuel for endurance, stored in muscles and the liver.
Not Just the Night Before: Effective carb-loading is a multi-day process involving a tapering of training and an increase in carb intake, not a single massive meal.
Low Fiber is Key: Opt for low-fiber options like white pasta and simple sauces to ensure easy digestion and prevent gastrointestinal issues on race day.
Practice Your Meal: Never try a new meal on race day; practice your pre-race fueling during training runs to see what works best for your body.
Balanced Fueling: The pre-race meal should be carb-heavy with moderate lean protein and low fat and fiber, rather than just an excessive amount of carbs.
Avoid the Wall: Proper carb-loading prevents hitting the dreaded "wall," the point where glycogen stores are depleted and fatigue sets in.

The Science Behind Carb-Loading

The practice of runners eating pasta the night before a race is rooted in solid sports science. For endurance athletes, carbohydrates are the body's most readily accessible and efficient source of energy. When consumed, carbohydrates are broken down into glucose, which is then stored in the muscles and liver as glycogen. These glycogen stores act as a personal fuel tank for your race. During intense, long-duration exercise, your body uses this stored glycogen for energy. As glycogen stores deplete, fatigue sets in, often referred to as "hitting the wall". Carb-loading is a strategic process designed to maximize these glycogen stores, preventing or delaying this fatigue.

More Than a Single Meal

A common misconception is that carb-loading involves a single, massive pasta dinner just before the race. Effective carb-loading is a strategic process that begins several days in advance, typically during the tapering period of training. During this time, runners decrease training intensity while increasing carbohydrate intake. The night-before meal serves as a final top-up and should be easily digestible, focusing on simple carbs, moderate protein, and low fiber. Avoiding a huge, heavy meal is crucial to prevent gastrointestinal distress.

Why Pasta Is the Classic Choice

Pasta is a popular choice for carb-loading due to its high carbohydrate density, making it efficient for glycogen storage. Plain pasta with a simple sauce is easy to digest, reducing the risk of stomach issues. White pasta is particularly favored for pre-race meals due to its low fiber and fat content, allowing for quick processing. Familiarity with pasta also offers comfort and reduces stress before a race.

Not All Carbs Are Equal: A Comparison

While pasta is a classic, runners have other excellent options for carb-loading. The key is choosing a high-carb source that is low in fiber and fat in the days leading up to the race.


Carbohydrate Source	Glycemic Index (GI)	Fiber Content	Digestion Speed	Best For	Considerations
White Pasta	Lower-Medium (cooked al dente)	Low	Moderately Fast	Pre-Race	Easy to digest, versatile. Pair with simple, low-fat sauce.
White Rice	High	Low	Very Fast	Pre-Race	Excellent for quick glycogen replenishment, especially right after a long run.
Potatoes (peeled)	High	Low	Fast	Pre-Race	Great source of potassium and quick energy.
Whole-Wheat Pasta	Medium-Low	High	Slow	Recovery	Too much fiber can cause stomach issues before a race.
Oatmeal	Low	High	Slow	General Fuel	Great for daily energy but can be too fibrous close to race day.

The Proper Pasta Meal: What to Pair It With

Choosing the right sauce and protein is important. Opt for simple, easy-to-digest options like a low-fat tomato-based sauce. Avoid cream-based or high-fat sauces as they slow digestion. A small serving of lean protein like grilled chicken or fish is suitable, but avoid heavy, fatty, or spicy foods that could cause stomach upset.

Common Carb-Loading Mistakes

Runners can make mistakes that hinder performance. Avoid overeating, as the goal is to increase carb percentage, not just total food volume. Effective carb-loading requires several days, not just a single meal. High-fiber foods can cause digestive issues before a race, so switch to low-fiber options. Always practice your pre-race fueling strategy during training runs instead of trying new foods on race day.

Conclusion

Eating pasta the night before a race is a scientifically supported strategy for endurance athletes, helping to maximize glycogen stores and delay fatigue. Success depends on proper execution, including increasing carbohydrate intake over several days, choosing low-fiber options like white pasta with simple sauces, and avoiding digestive issues. A well-planned pre-race fueling strategy is crucial for endurance performance.

For more information on proper race nutrition, consult an expert or refer to reliable sources like Runner's World.

Frequently Asked Questions

Carb-loading is primarily for endurance events lasting over 90 minutes, such as a half or full marathon. For shorter races like a 5k or 10k, a normal, balanced diet with adequate carbs is sufficient, as your body's standard glycogen stores are enough.

For your pre-race meal, opt for white pasta over whole-wheat. The lower fiber content in white pasta makes it easier and faster to digest, reducing the risk of stomach discomfort during the race.

Choose a simple, low-fat, and non-spicy sauce like a basic marinara. Avoid heavy, cream-based, or oily sauces and excessive spices, which can slow digestion and potentially cause stomach issues.

Yes, effective carb-loading can cause a temporary weight increase of 1-2 kilograms. This is because every gram of stored glycogen is also stored with 3 grams of water, which helps keep you hydrated during the race. This weight is temporary and beneficial for performance.

Excellent alternatives include white rice, potatoes (peeled), oatmeal (if not too fibrous), quinoa, and bagels. The best choice depends on what your body tolerates best, which you should test during training.

Your final carb-heavy dinner should be eaten on the early side the night before your race to allow ample time for digestion. You should aim to feel comfortably fueled but not overly full on race morning.

If nerves affect your appetite, stick to very simple, easy-to-digest carbs. Options include a plain bagel with jam, a banana, or even a sports drink or juice. These can help top off your energy without causing discomfort.