How to Boost Carb-Loading Before a Cycling Race

Most cyclists and triathletes have heard about and experienced the consequences of insufficient carb-loading before races.

Carbohydrate loading has been used for many years to boost performance in cycling races lasting more than two hours in duration.

While there are various methods of carb-loading, the process involves consuming large quantities of carbohydrate-rich food to fill the muscle glycogen stores.

More muscle glycogen protects you from (or delays) exercise-induced hypoglycemia and helps you exercise longer at high intensity.

Please remember to practice your carb-loading plan well before your priority race.

Since carb-loading only lasts a few days, there are no reasons to worry that some minerals and vitamins are not represented sufficiently in your carb-rich diet.

After the race, you return to your routine, balanced diet, and that’s fine.

It is essential to know that you also increase your body mass when carb-loading. Remember that every gram of glycogen stored is associated with app. 2.7g of water. So you can expect a body mass gain from app. 2kg when you are fully loaded with carbohydrates. This is important to know and may influence your decision on whether you should carb load or not.

Many experiments have been performed to find the perfect method for carb loading before races. The best-known method is the carbohydrate-depletion/carbohydrate loading method. The theory behind this strategy is that exercising to exhaustion six days before your primary race combined with a low-carb diet until three days before the race depletes muscle glycogen.

When your glycogen stores are completely depleted, the theory is that your muscles are hungry after storing glycogen and can ‘super-compensate’ the last three days before the race. So it should be possible to store even more glycogen than through regular carb-loading procedures.

I’ve tried the depletion-load method once, and I ended up being well-loaded for the event.

Though, it is a bit problematic to train to exhaustion just six days before a priority race followed by low-carb dieting. That’s not optimal tapering. So the carbohydrate-depletion/carbohydrate loading method works best in theory. And the approach has not proved to achieve higher glycogen content than regular three-day carb-loading in scientific studies.

In practice, you can reach full benefit from carb-loading just three days before your priority race:

Here is my advice for optimal carb-loading:

1) Consume 7-10g carbohydrate per kg body weight per day.
If you are highly trained,
you should probably aim for close to 10g/kg body weight /day the last three days before your race. You can achieve great results with just one day of concentrated carb-loading if you are out late.

2) Minimize fibre-rich food
Since many carbohydrate sources contain fibers, you may need to prefer carbohydrate sources with a low content of fibers. However, large quantities of fibers may cause flatulence, diarrhea, gastric and gut discomfort.

So it is recommended to choose a high-carb, low-fiber diet (white bread, white pasta, white rice, liquid forms of carbohydrates, etc.)

3) Increase fluid intake
As mentioned above, carb-loading is associated with water, so you’ll need to drink more fluids to stay well hydrated. Fluids can also be seen as a source for carb-loading if you don’t want to eat pasta all day long, e.g., soft drinks, juice, sports drinks, etc.

Again, make sure to test your carb-loading procedure BEFORE you enter an important race. We are all different, and you might need to make individual customization to get a perfect diet plan.

Finally there is a sweet little ninja trick that may boost your carb-loading:

When I have athletes at cycling races, I always ask them to do a short, high-intensity interval the day before. This is both mentally and physically a great way to prepare their bodies for competition.

This little trick also increases the glucose uptake at a minimal cost of muscle glycogen in the mirror of carb-loading.

Thus, you might end up maximizing your glycogen storage and being physically and mentally prepared for action.

Cool, right?

Jesper Bondo Medhus

I am a medical doctor with a special interest in cycling training. I work at the Hospital of Vejle using clinical physiology and nuclear medicine to diagnose cancer and heart patients. I have written two e-books: Time Effective Cycling Training and 12-Week Winter Training Program.

View Comments

  • An article of a university tells me that you should consume 5 - 7 g for each kilogram of weight. You should start 48 hours before the race.
    They say that your body needs 24 to 48 hours for storing the carb in the muscles.

    Both stories are rather similar but what's best ??

  • My article is also based on scientific literature. It's clear that there will be different conclusions if you go through several papers, websites and books. Though, I suppose most nutritionists would agree that 7 to 10g carbohydrate per kg body weight is appropriate for a highly trained endurance athlete. Less than 7g per kg body weight is probably not enough to load carbohydrates sufficiently.
    I agree that the difference between 48 to 72 hours cargo-loading is minimal (if any).

  • Hi Jesper, Thanks for the article on carbo loading, something I have know about for many decades.
    What I have never had explained to me is with all this carbohydrate [sugar] being consumed what is happening with the the pancreas and insulin production that would be knocking down the rise in blood sugar and the liver making fat ?
    This carboloading seems to go against all the facts that one should keep sugar and processed grains to a minimum except when actually exercising.
    Your comments please.

  • How short is the high intensity workout the day before competition? Can you be specific? How hard is the intensity? Above FTH? How many intervals and how long are they? Thanks.

  • Mostly I use app. 5 min at threshold power. Recently, I have also been experimenting with even shorter duration at power outputs above threshold power. It's clear that these intervals must never be exhausting.

  • @Westly - If you are a healthy person then your pancreas will release insulin that induces a rapid increase in the glucose uptake in your muscles. Increasing the total amount of glucose (stored as glycogen) enhances your performance at endurance events lasting more than 1.5 hours.

  • Hi Jesper,
    I have always experience cramps in my hamstrings after 100km during long rides. I will certainly try carbo loading as recommended. In addition, what is your advice on nutrition during the ride itself ie energy gels and electrolytes during what time intervals. I'm also using Perpetuem ( hammer product) during the rides.
    Thanks.

  • So you do approx. 5 minute intervals at FTH; If your interval is 5 min., what length is the recovery between sets? 5 min. as well? Do you cap your workout at say 30 minutes excluding warm-up and cool-down? Say 5-6 intervals? I am doing a sprint race in about a week so I'm assuming I need to keep my workouts during taper week short. Thanks again!

  • 5-7 is good enough between training (high volume)
    7 tot even 12 g/kg BW you need idd to maximize glycogenstores before a race or major event....
    It also differs a bit of the amount of muscle mass: more muscles = higher storage
    1 kg "wet" muscles contains about 15g glycogen
    and roughly 40% of the body are muscles: so when you weight 70kg , you have about 28 kg muscle mass => about 420 glycogeen
    just try to eat 350-550 g carbs three days before major event to maximize glycogenstores

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Jesper Bondo Medhus

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