How to carb load before a long run or race

Ivory Lira, RDN - Registered Dietitian Nutritionist

Knowing how to carb load in the days leading up to an endurance event can help you avoid "hitting the wall," which is when your body runs out of glycogen–or stored carbohydrates. Applying what you read here can make the difference between finishing strong and struggling through those final miles.

Why knowing how to carb load matters

Carbohydrate loading helps maximize your muscle glycogen stores. This is the primary fuel that your body uses during prolonged exercise. Increasing your carb intake 2-3 days before a race, while you’re in your tapering phase, allows your muscles to store more glycogen than usual. Knowing how to carb load properly can help delay fatigue and maintain your energy for a longer period during your run.

Calculating how much to eat

The general guideline for how to carb load is to aim for 8-10 grams of carbohydrates per kilogram of body weight per day during the final 2-3 days before your race. For example, a 150-pound (68 kg) runner should consume 545-680 grams of carbohydrates per day. Including foods like pasta, rice, potatoes, bread, fruit, and even sports drinks can help you reach the recommended amount of carbs. Keeping meals high in carbs, moderate in protein, and low in fat and fiber helps avoid stomach discomfort and eases carbohydrate absorption.

Practical carb-loading tips

Start your carb load about 3 days before your event, gradually increasing your intake of carbohydrate-rich foods while also reducing your training intensity. Spread your carb consumption throughout the day between breakfast, lunch, dinner, and snacks, to make it easier to reach your target.

Carb-loading ideas:

Oatmeal topped with banana and honey for breakfast
A sandwich on a roll or bun with fruit at lunch
Pasta with red sauce and a small side of lean protein for dinner
Sports drinks and pretzels for snacks

The day before your race, focus on familiar foods, hydrate well, and avoid anything that could upset your stomach.

Understanding how to carb load effectively ensures your muscles are fully fueled for race day. Focusing on hitting your carb targets and sticking with easy-to-digest foods will help you maintain your energy and the fuel needed to carry you strong through the finish.