Carbo loading 101

Carbo loading 101

Carbo loading 101

Carbo load ” is one of the most common nutritional tools, often used by athletes to improve performance. This involves adjusting your diet and physical activity levels to increase the amount of carbohydrates stored in your body through food.

In today's post we will talk about this “loading” of carbohydrates, point out some common mistakes and provide recommendations on how to do it correctly. Let's go!

Stocking up on carbohydrates essentially aims to supersaturate muscle and liver glycogen, the storage form of carbohydrates in the muscles and liver, respectively, a few days before the target event. The intention of maximizing muscle glycogen is to prepare you for race day with stored energy reserves and not let your body run out before the finish line. Ensuring this maximum carbohydrate storage also gives your muscles the best chance of recovery, you know?

Gabi, is the carbo load everything it promises? Will this really make a difference in performance? As with many other questions and answers in nutrition… it depends.

This strategy typically involves several days of eating more carbs than usual while decreasing your workout volume to reduce the amount of carbs you're using. The amount of carbohydrates you can consume on loading days varies from 5 to 12 grams per kg of body weight per day. If you are mildly active but don't compete or do long training sessions, increasing your carbohydrate stores probably isn't necessary for you. What's more, if you eat more carbohydrates when you don't need to, you may end up changing your normal diet unnecessarily or consuming more calories than your body needs.

Carbo loading specifically may be appropriate for exercises that lead to large reductions in the amount of glycogen in muscles, such as cycling or prolonged running. Research has shown that carbohydrate loading can reduce fatigue and improve performance by 2–3% for workouts lasting longer than 90 minutes. However, it is probably not effective for shorter periods of exercise or types of exercise that involve short periods of activity, including weight training.

Bottom line: Your body stores carbohydrates in the form of glycogen. Carb loading is a strategy to increase your glycogen storage and improve exercise performance. It may be effective in events lasting more than 90 minutes, but is probably unnecessary in training and events of shorter durations.

There are several specific carb loading programs (6-day, 3-day, 1-day programs). The main differences between them are the duration and the amount of exercises they include. All programs utilize a short-term high-carb diet while temporarily decreasing exercise.

The one-day program is the simplest of all and includes the following strategy: You do not exercise for a day and consume a carbohydrate-rich diet of around 10g/kg of body weight.

Before starting any strategy, there are several common mistakes you should be aware of:

Eating a lot of fat

Some people make the mistake of choosing foods high in carbohydrates and fat rather than just carbohydrates. While fat can be part of a balanced diet, as you are increasing your carbohydrate intake, reducing your fat intake can help you avoid eating too many calories. Eating too much fatty foods can cause weight gain or make you feel sluggish and “heavy.” For example, many desserts such as chocolate, ice cream and cookies fall into this category, as do creamy pasta sauces chosen the night before.

Eat a lot of fiber

Eating foods rich in fiber can also be harmful. Although fiber is part of a healthy diet, too much fiber can cause stomach upset in some people. The carbo load period is a unique time when it would be better to choose white bread (warm French bread) instead of wholemeal bread. During this time, you should probably also avoid fiber-rich foods like beans and salads.

Eating new or unusual foods

The days leading up to your event or competition are important, and stomach upset from unfamiliar foods can hamper your exercise experience and performance. Therefore, you should choose foods that are already familiar to you – as well as being rich in carbohydrates, low in fat and low in fiber. On the day of the race we didn't test anything new and that goes for the food before the event, too!

Keep training a lot

Lastly, not decreasing or “reducing” the amount of exercise you perform during the carb load period can allow glycogen stores to increase, after all, they are being used and not stored.

Here are some examples of foods that are high in carbohydrates, low in fat, and don't contain a lot of fiber:

Fruit juices

White pasta with red sauce

White bread

White rice

Skinless English potato

Fruit compote

Fruits, including bananas and oranges.

White flour, used in cooking

Fruit ice cream

Sports drinks

Of course, it is also important to have protein in your meals to regenerate and feed your muscles. Try to focus on lean protein sources, such as fish, lean cuts of meat or poultry, and fat-free dairy products, such as white and light cheeses.

To recap: Carb loading is a nutritional strategy for increasing exercise performance and involves two main components: increasing the amount of carbohydrates you eat and decreasing the amount of exercise. Carbohydrate intake can vary, but experts generally recommend a tighter range of 8 to 10 grams per kg of body weight. It's a strategy that can improve performance in exercises lasting more than 90 minutes, but is probably unnecessary for short-duration activities.

And don't forget to choose familiar foods that are high in carbohydrates and low in fat. Also pay attention to the amount of fiber you ingest during these days - after all, we don't want any unpleasant surprises!

Thanks for reading and see you in the next post!

Gabi, nurturer at Z2


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Sherman WM, Costill DL, Fink WJ, Miller JM. Effect of exercise-diet manipulation on muscle glycogen and its subsequent utilization during performance. Int J Sports Med. 1981 May;2(2):114-8. doi: 10.1055/s-2008-1034594. PMID: 7333741.

Jeukendrup AE. Nutrition for endurance sports: marathon, triathlon, and road cycling. J Sports Sci 2011;29 Suppl 1:S91-9. doi: 10.1080/02640414.2011.610348. Epub 2011 Sep 15. PMID: 21916794.