Carb-Loading for the National Gravel Championships: A Cyclist’s Guide
As the National Gravel Championships approach, it’s easy to become intensely focused on the products and nutrition strategies you will use during the race. However, one crucial aspect that often gets overlooked is the importance of adequate carbohydrate consumption in the days prior. Research suggests that “carbo-loading” can prolong your exercise capacity by up to 20%, resulting in a significant increase in performance.
Our experience of working with athletes shows that there is sometimes confusion over how far in advance the carbo-load should start, and how much “extra” should be eaten. By looking at the science, plus experience of what works practically, we have put together a short guide on how to effectively carbo-load.
The Evolution of Carb-Loading
Starting an endurance event with the muscles and liver full of glycogen is imperative. A nice way to visualise this is thinking of your muscles like a cars fuel tank; you want to start your journey with the tank as full as possible to maximise the distance you can travel. I’m sure you’ve all experienced the feeling of “bonking”, which is essentially when the cars fuel tank (or your muscles) are empty, you’re not going anywhere fast! More specifically, this is what happens when muscle glycogen becomes significantly depleted.
As early as the 1920's, scientists understood the importance of carbohydrate metabolism in exercise performance, and how subsequent carbohydrate feeding could prevent fatigue. However it wasn’t until the 1960's that this was confirmed (through new muscle biopsy techniques) and the carbo-loading concept, “supercompensation” was born.
The supercompensation theory, developed by Bergstrom & Hultman suggested that athletes underwent a depletion phase followed by a week-long carbohydrate-loading protocol. This method involved a period of intense training with a low-carb diet to deplete glycogen stores, followed by a high-carb diet to “supercompensate” glycogen levels. Recent research however, indicates that such extensive protocols are unnecessary. Modern strategies now focus on combining the effects of a taper (a reduction in training volume in the days leading up to a race) with increased carbohydrate consumption to induce the same effects.
The Modern Approach
The latest guidance suggests that well-trained cyclists should start to consume more carbohydrates 48 hours before an event, specifically, a whopping 8-12 grams of carbohydrates per kilogram of body weight, per day! We have however found that adopting a staggered approach of 5-7g per kg of body weight 2 days before, and 8-12g the day before works best. This approach is both more practical and equally effective in ensuring glycogen stores are maximised.
The table below references the total grams of carbohydrate this equates to according to body weight (taking the average quantity for each day)
Optimal Carbohydrate Sources
During the carb-loading phase, focus on easily digestible, high-glycemic index (GI) carbohydrates such as:
- White rice
- Pasta
- Rice noodles
- Potatoes
- Pancakes
- Low-fibre cereals
- Fizzy drinks!
A key piece of research (Coyle et al) shows that over a 24 hour period muscle glycogen stores were 50% more full through consumption of high GI foods compared with low GI foods. It may sound surprising but food and drinks such as Haribo, Coke or even your carbohydrate drink mix are all great options!
Reducing Fat and Fibre
Carbo-loading doesn’t mean over-eating to the point of explosion; it means eating a greater volume of carbohydrates in proportion to other macronutrients.
To accommodate the increase in carbohydrates, it's wise to reduce your intake of fats and fibre. High-fat foods can slow digestion, and high-fibre foods can cause bloating and discomfort. By reducing these, you create more room for carbohydrates, ensuring your body can handle the increased intake without adverse effects. For some of our athletes it’s possible to consume over 6000 kcal the day before an event, whilst only eating 30g fat.
The Role of GLUT4 Transporters
In the days leading up to the race, incorporating race openers (short, intense efforts) can be beneficial, not only for keeping the legs fresh but also to enhance glycogen storage. These efforts will stimulate GLUT4 transporters, which are responsible for glucose uptake into the muscles. Enhanced GLUT4 activity ensures that the glucose you eat post openers will be stored as glycogen in your muscles. Think of it as a way of “banking” the carbohydrate, so it’s there ready to use on race day.
Caution for Low-Carb Diet Followers
For cyclists who typically follow a low-carb diet, suddenly, and significantly increasing carbohydrate intake can lead to GI distress. To avoid this, it’s advisable to gradually introduce more carbohydrates a few weeks before the event, in what is referred to as “micro-doses”. By frequently micro-dosing amounts of up to 25g of carbohydrate, your body will gradually adapt to the higher carb intake, reducing the risk of discomfort whilst optimising your glycogen stores.
Expect the Scale to Tip
If you use the scales each day it’s normal to see an increase in body weight during the carb-loading phase. This is because for every gram of stored glycogen, your body retains three grams of water. So if for example you have managed to store 500g of glycogen in your skeletal muscle (this is an average capacity) expect the scales to read 2kg more! This temporary weight gain is a positive indicator that your glycogen stores are full, providing the energy reserves needed for peak performance during the race.
In summary, while focusing on race-day nutrition is essential, don’t underestimate the power of effective carb-loading in the days leading up to the Championships. By following modern carb-loading protocols, choosing the right carbohydrates whilst reducing fat and fibre, you can ensure your glycogen stores are maximised. Keep in mind the importance of GLUT4 transporters and the need for gradual adaptation if you usually follow a low-carb diet. Embrace the temporary weight gain as a sign of well-fuelled muscles ready to conquer the gravel roads ahead.
Prepare wisely, fuel adequately, and race with confidence!
Good luck!
Sophie Parker- DEEKA
