Carbohydrate Loading

This post is adapted from Nutrition for Cyclists: Eating and Drinking Before, During, and After the Ride, a forthcoming ebook which I will be publishing for Kindle on

Nutrition for Cyclists: Eating and Drinking Before, During and After the Ride can now be purchased on  For information about the book and how it relates to what I’ve posted to Tuned In To Cycling, please check out this post.

eating spaghettiWell-organized and popular century rides often offer an all-you-can-eat pasta dinner the night before the ride.  If you go to the dinner, you’re likely to see people putting away enormous plates of pasta and if you ask them why they’re eating so much spaghetti they’ll tell you that they’re carbo loading for the next day’s ride.  What is carbohydrate loading and is eating a lot of spaghetti the night before a big ride the right way to go about it?

The basic idea behind carbohydrate loading is that glycogen stores in the muscles and liver can be increased over the norm by following specific exercise and dietary regimens in the days before a ride.  The increased glycogen stores should then translate into a longer time before fatigue sets in due to glycogen depletion during the ride. There are three recognized carbohydrate loading methods and I will suggest an alternative approach.

The original and most severe method follows a week-long regimen. On the 7th day before the ride, you exercise to exhaustion.  This exercise bout should last a minimum of 90 minutes.  The next 3 days are a carbohydrate depletion phase during which you train lightly while keeping carbohydrate intake at only 10% of your daily caloric intake.  The final 3 days before the big ride are a carbohydrate loading phase.  You continue to train lightly while jacking carbohydrate intake up to 70% of your daily caloric intake.  It’s important not to increase your total caloric intake from the norm over the 6 days of carbohydrate depletion and loading.  During the 3 day depletion phase you replace calories normally consumed in carbohydrates with calories consumed in fats and proteins. During the 3 day loading phase your replace fats and proteins with carbohydrates.

drink-b4-thirsty-mod-4-customThink about this for a minute.  The depletion phase is an extended period of controlled hypoglycemia, essentially a 3 day bonk.  During that time you can be expected to experience all of the negative effects of bonking including weakness and lethargy, anxiety, depression, hostility, feelings of hopelessness and failure, low levels of emotional control, reduced awareness of your surroundings and confused thinking.  In addition, the immune system will be depressed and you will be more susceptible to contracting an illness that may still be present when the ride comes several days later.

A 3 day bonk is hard.  Very hard.  The second method eliminates the bonk by eliminating the depletion phase. On the 7th day before the ride you have a long exercise session but you don’t exercise to exhaustion.  For the next 6 days you engage in progressively lighter exercise sessions each day.  Some people recommend tapering the level of exercise down to a day of rest on the 6th day.  For the first half of this 6 day period you ingest carbohydrates at a normal 55% – 60% of your daily caloric intake.  For the final 3 days you ramp carbohydrate intake up to 70% of your daily caloric intake, again by replacing fats and protein with carbs.

The third method is the easiest of the three. During the week before the big ride you exercise lightly and eat normally.  On the day before the ride you do a very short, 3 minute high intensity workout.  The workout should be made up of a 2.5 minute session at 130% VO2 max which is roughly equivalent to the fastest pace you can maintain over approximately 4 minutes of all-out running or cycling.  Follow this 2.5 minute effort with a 30 second flat-out sprint.  If done properly, this 3 minute workout is going to hurt.  During the following 24 hours ingest 12 grams of carbohydrates per kilogram of lean muscle mass.  Muscle mass can vary greatly depending on age, gender and degree of muscular development.  Based on a very rough average of 35% muscle mass for men and 27% muscle mass for women the carbohydrate intake over the 24 hour period would total approximately 305 grams for a 160 lb. male and 191 grams for a 130 lb. female.

If followed correctly, all three of these methods should produce a markedly enhanced level of glycogen storage on the day of the big ride.  Neither anecdotal reports (which are basically worthless) nor research studies have reached a clear consensus on how much better or worse one method is relative to the others.  The bottom line is that all three methods are effective if followed properly.

baby spaghetti dumpNow, I’ll suggest a fourth method that is usually not discussed in the literature.  Forget about it. Don’t bother with any of this stuff.

Wait . . . what? Consider the kind of riding you do.

If your ride takes less than 90 minutes, carbohydrate loading is a non-issue because proper eating before, during and after your previous ride should have adequately prepared you for the next ride.

If your ride takes longer than 2.5 or 3 hours, you’re going to have to eat during the ride anyway because even perfectly executed carbohydrate loading isn’t going to provide you with sufficient glycogen stores to last for this length of time.  All carbohydrate loading is doing is delaying the time before you have to start eating.

Wiggins eating_croppedIf your ride takes between 1.5 and and 2, maybe 2.5 hours, carbohydrate loading might allow you to get through the ride without ingesting any carbohydrates. But why would you want to do this? If you enjoy rides that last more than 90 minutes you would be much better served by becoming proficient at eating on the bike to fully supply your nutritional needs during the ride. You get better at what you practice and if you find a way to avoid eating on the bike, you’re not going to get better at eating on the bike.

The fundamental goal of cycling nutrition is to provide full nutritional support for your ride.  A competitive race, a long organized or training ride, and a Sunday afternoon toodle around the neighborhood all make different demands on your body but whatever the ride, you will do it better and enjoy it more if you provide the nutritional support the ride needs.  The simplest and most effective way to do this is to develop the habit of ingesting small amounts of carbohydrate regularly during the ride.  The best way to develop the habit is to practice doing it.

If properly carried out, carbohydrate loading can fully support rides lasting 1.5 to 2 hours, maybe a bit more, if you don’t ingest any other carbohydrates during the ride. It’s not much use for rides lasting less than 90 minutes or more than 2, maybe 2.5 hours.  Eating properly during the ride can fully support any kind of ride you want to do. The choice is yours.

4 thoughts on “Carbohydrate Loading

  1. I cycle with all the symptoms of bonking that you listed: weakness, anxiety, hostility…etc (April 26 2014) as I have Reactive Hypoglycaemia. I usually do 250 mile touring trips, and have done Col de la Madeleine and Lands End to John O’Groats (slowly!). Trickle eating, or as you put it becoming proficient at eating on the bike, is the only thing that enables me to do it. I need to eat 10 times a day for normal life and more than twice that when cycling. I have nuts, hard cheese and dried apricots stuffed in my 3 back pockets and Rye bread, more cheese, apples, and sardine tins in my saddle bag: and still have to find a friendly cafe midday. I would be very interested in your book on nutrition as I would like to learn more – please write it soon! All the doctors I’ve met are ignorant about food, and Nutritionists do not understand endurance sports!
    Does anyone else cycle with RH?

    • Chapeau! Riding 250 miles is hard. Riding any miles with RH is beyond hard. Endurance cycling is tough enough for someone without physical problems or complications. One time Laura and I did a week-long bike tour from Albuquerque, New Mexico to Denver, Colorado with a group of people. We usually treat these things like cycling vacations and ride at a relaxed pace but one day on this tour we had to do a section of road that was about 40 miles long, dead straight, and almost flat. It was nothing but boring and tedious. In order to get it over with as quickly as possible, we switched into training mode. I put my head down and rode hard tempo while Laura hugged my wheel. At the end I looked up and one guy from the group had been able to hang with us at the pace I’d set. He was whipped but he was there. He was also the one guy in the group with an implanted insulin pump to help him control his diabetes. He also was in the early stages of MS. I couldn’t believe it and thought maybe the van that carried the rider’s luggage from one night’s stop to the next had taken him most of the way and he had hooked on at the end but Laura said, no, he had been on her wheel the whole way. Throughout that entire tour he was the only other rider who could consistently ride hard each and every day. You guys who do this with medical problems that make it much more difficult than it is for the rest of us are awesome.

      • Thank you for your reply. I’ve been on bikes since 1954 and I don’t want to give it up – it’s as simple as that! Perhaps your fellow traveller had a similar motivation, he certainly had a lot to deal with. I am trying to learn how to balance the see-saw between blood glucose, insulin and adrenaline, which involves food intake and mental control. Can I say it’s cyclelogical?

    • By the way, it seems you, of all people, might in fact benefit from the low glycemic index ‘superstarch’ that was trounced so soundly here recently 🙂
      Of course, constantly nibbling on small bits of food does same trick, but this stuff might make life a bit less of a hassle. No idea how expensive this stuff is, though. Given the marketing budget, I suspect they do like 10x markup at the very least.

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