Tag Archives: glucose

Nutrition for Cyclists

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N4C_AmazonFirst of all, an enormous vote of appreciation and thanks to all of the readers of Tuned In To Cycling over the years who have provided helpful comments, support and motivation for me to write a book about cycling nutrition. It’s finally happened. Nutrition for Cyclists: Eating and Drinking Before, During and After the Ride is now available for purchase at Amazon.com.

The book grew out of the nutrition posts here on Tuned In To Cycling and, like those posts, combines suggestions and recommendations for what to eat and drink before, during and after a ride with information about how the body responds to endurance athletics.  To help you decide whether or not you’d like to purchase the book, I’m posting the book’s Introduction here which will give you a good idea about what’s in the book and how it relates to the posts that have appeared on Tuned In To Cycling.

If you decide to buy the book and you think it is useful for other cyclists and worth a 4 or 5 star review, I would greatly appreciate it if you would leave a review on Amazon.  Positive reviews are a huge factor in helping a self-published book find an audience among the millions of ebooks published on Amazon.

Here’s the Introduction to  Nutrition for Cyclists: Eating and Drinking Before, During and After the Ride.

Chapter 1. Introduction

Here’s a quote from former U.S. President John F. Kennedy that many cyclists know well.

Nothing compares to the simple pleasure of a bike ride.

Anyone who has spent any time on a bike knows that it’s true . . . . until it isn’t.
Here’s another saying cyclists know well.

Eat before you’re hungry, drink before you’re thirsty.

Short of a catastrophic accident, nothing can turn a pleasant, joyful or exhilarating bike ride into a nightmare faster than failing to provide your body with the nutritional support it needs to carry out the ride. Nutrition for Cyclists is designed to give riders of all experience levels useful information about meeting the nutritional demands imposed on the body by endurance athletics. Good nutrition can help you get the most out of your ride no matter what kind of ride you like to do.

Finally, one more saying that everybody knows.

Give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime.

Nutrition for Cyclists contains recommendations about what to eat and drink before, during and after a ride. That’s the “give-a-man-a-fish” part. However, no book can give you a recipe for what to do in every possible nutrition-related situation that might arise when you’re riding the bike. Even if a book like this were possible, would you want to memorize it so you would be prepared for anything?

Nutrition for Cyclists also contains a good deal of information about how your body works when you’re engaged in athletic activity. That’s the “teach-a-man-to-fish” part. The more you know about how your body processes food and drink, and about what can happen when there is not enough food or drink for your body to process, the better prepared you’ll be to understand what’s happening to you on the bike.

The short-term goal of Nutrition for Cyclists is to get you started with recommendations about eating and drinking before, during and after a ride. The long-term goal is to give you information about nutrition and endurance athletics so that you will be able to make informed decisions about what’s happening to you on the bike and what you can do to make it better.

The information presented in Nutrition for Cyclists is based on research findings reported in peer-reviewed journals in the fields of human physiology, and nutrition and sport science. The internet is awash with assertions, recommendations, and unsubstantiated claims about exercise nutrition. Some of this advice is supported by sound research. Much of it, including a number of widely cited and uncritically accepted ideas, is not. As will be discussed in the next chapter, focusing on information that is well supported by sound research does not mean that everything in Nutrition for Cyclists is “right” or “true”. It means that this information is the best we have given the current state of scientific research on exercise nutrition.

Nutrition for Cyclists grew out of a series of posts on Tuned In To Cycling, a blog I started in the spring of 2008. While Tuned In To Cycling has posts on many cycling-related topics, the posts on nutrition have proven to be the most popular with cyclists from all over the world. Some of the content of this book has been copied verbatim from the posts on Tuned In To Cycling, some of it is a revised or rewritten version of what’s on the blog, and some of it is new. Everything in Nutrition for Cyclists was checked against the current research literature. If a section of the book has been lifted verbatim from the blog, it means that research published between the time the original post was written and the book was published did not demand changes in the information that had appeared in the blog.

For both new readers and followers of Tuned In To Cycling Nutrition for Cyclists provides the convenience of a self-contained source for nutritional information that is organized into sections devoted to what to eat and drink before, during and after a ride. Also, publication as an ebook means Nutrition for Cyclists is conveniently available anywhere you have a Kindle or any other device with a Kindle app.

Cycling Nutrition: The Basics – Glucose, Glycogen and Carbohydrates

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More information about the basics of fueling the muscles and hydration can be found in Nutrition for Cyclists: Eating and Drinking Before, During and After the Ride which can be purchased on Amazon.com.  For information about the book and how it relates to what I’ve posted to Tuned In To Cycling, please check out this post.

While proper nutrition is one of the most important factors affecting long-distance cycling on a day-in, day-out basis, there is so much misinformation out there that knowing what to eat and when to eat it can be Burning glucosedifficult.  Part of the reason for this is that it’s early days yet for nutrition science; much remains to be learned and nutritional theories are often revised as new information becomes available.  Another reason is that the subject of sports nutrition is confused in the minds of many with the subject of dieting.  Unfortunately, dieting in the US is a multimillion dollar industry that is fat with fads and outright foolishness.  Finally, many cyclists seem to have a deep emotional commitment to their cycling-related eating habits and resist change.  In these Cycling Nutrition posts I’ll try to present nutritional information that is based on research found in peer-reviewed scientific journals on nutrition and cycling and endurance sports in general.  In this post we look at the basics of how muscles are fueled that underlie every discussion of nutrition for cyclists. In other posts we examine eating during a ride, eating after the ride, and bonking.

Muscles burn glucose for energy.  The longer you ride or the faster you ride, the more glucose your muscles need for fuel.  When you get on the bike and start pedaling, the demand for glucose for your leg muscles increases and a signal goes out to the body to start supplying the glucose you need.

Glycogen and glucose

Where does the glucose come from?  The body doesn’t store raw glucose.  Instead, it makes glucose from other substances.  Glucose can be derived from breaking down stored fat and protein.  Subcutaneous fat (the excess fat stored under the skin) is an especially good energy source because fat contains roughly twice the number of calories as either protein or carbohydrate.  This means you get more fuel in the form of blood glucose from breaking down a gram of fat than from a gram of either protein or carbohydrate.  Indeed, breaking down stored fat to increase the level of blood glucose is the reason why exercise leads to weight loss.  The problem with relying on breaking down fat to produce glucose is that the process is relatively slow and energy intensive.  Metabolizing (breaking down) fat can be a useful long term source of energy but it is too slow and inefficient to support immediate and short term demands for glucose to fuel ongoing athletic activity.

In order to have fast access to glucose when needed, excess glucose in the blood is stored in a form known as glycogen.  Glycogen can be quickly broken down to supply glucose as needed.  The main storage locations for glycogen in the body are the muscles and the liver.  Liver glycogen is volatile in the sense that it doesn’t last long.  This is because liver glycogen serves as an energy source for the entire body.  When liver glycogen is metabolized the glucose that is produced enters the blood stream and can be used any place in the body where it’s needed.  If you go to bed with with liver glycogen stored at maximum capacity, a large proportion of it will be gone when when you wake up because it was used to fuel the body’s needs while you slept.

Muscle glycogen is more stable in the sense that once stored it remains in place much longer.  This is because muscle glycogen does not enter the bloodstream.  The glycogen stored in an individual muscle can only provide glucose for that muscle.

So, you’re pedaling along burning glucose derived from glycogen stored in your liver and your cycling muscles and everything’s just peachy.  Until you run out of stored glycogen.  The body can store enough glycogen to support approximately 90 minutes of moderate intensity exercise.  What happens when that glycogen is used up?  Where do your muscles get the glucose they need to keep working?  Some of it can come from fat that has been slowly breaking down while you’ve been riding but that won’t be enough to supply your needs.  Once you’ve exhausted your glycogen stores, most of the glucose you need is going to come from what you’ve been eating and drinking during the ride.  This is where carbohydrates enter the picture.

Basic nutrition for any endurance sport such as cycling is primarily about carbohydrates for the simple reason that carbs can be broken down to supply glucose much more quickly and efficiently than either fats or proteans.  While you’re on the bike you need a steady supply of carbs to both fuel ongoing activity and stretch the time before your stored glycogen is completely exhausted.  When you’re off the bike you need carbs to replace the glycogen you burned during the ride you just finished.  For anyone engaged in an athletic activity that lasts for 90 minutes or more, carbs are what basic nutrition is all about.