On an endurance ride a roadie is cruising along at a conversational pace, burning fat for fuel. Climbing a fairly steep hill, the roadie also starts burning glucose for fuel.
The harder the roadie is going, the greater proportion of the rider’s energy comes from glucose. You can store 1,500 to 2,000 calories of glycogen in your body, which your body metabolizes as glucose to fuel your muscles.
On a longer ride with real climbing, on a shorter club ride hammering with your buddies, and during an interval workout, you’re burning lots of glucose. When you run out of glucose your legs are leaden and your brain is fuzzy (it can only burn glucose) — you’ve bonked!
Because of these metabolic pathways, most coaches recommend a daily diet that is high in carbohydrates. Your body converts carbs to glycogen. We coaches recommend primarily carbs because training hard depletes glycogen stores, and if your glycogen stores are depleted, you won’t train as well the next day.
Carbohydrates include vegetables and fruit, as well as starches like bread, pasta, rice and potatoes.
Ride nutrition also emphasizes carbs. For exercise lasting more than an hour, the American College of Sports Medicine recommends starting to eat in the second hour. The ACSM recommends 30 grams (120 calories) of carbs per hour.
Another reason to emphasize carbs is that chronic glycogen depletion is one of the causes of overreaching and potentially overtraining.
Should You Eat a High-Carb Diet?
Nancy Clark’s Sports Nutrition Handbook (2008) and Clark and Jenny Hegmann’s The Cyclist’s Food Guide (2012) both discuss at length day-to-day nutrition to support cycling. They recommend:
Daily Diet with Carbs as the Primary Macronutrient
|Macronutrient||% of Total Calories||Calories / gram||Healthy examples|
|Carbohydrate||60 – 65%||4||Vegetables, fruits, grains, pasta, bread, rice and potatoes; and limit sweets|
|Protein||10 – 15%||4||Low-fat dairy, eggs, fish, poultry and lean meat|
|Fat||25%||9||Olive oil, canola oil, nuts, avocado and fish|
Too complicated? At each meal your plate should be primarily covered with a variety carbohydrates, with a serving of lean protein about the size of a deck of cards, and limited fat. (See the photo.)
Should You Eat a High-Fat Diet?
In Fast After Fifty (2015) Joe Friel describes a different daily diet in which at least 50% of your calories come from fat, i.e., increase the calories from fat and decrease the calories from carbs proportionally in the above table.
When fat is the primary macronutrient, then ketones, not glucose, are the primary energy source. Ketones are produced by the liver from fat. Your skeletal muscles, your heart, brain and other vital organs all function normally on ketones once the body adapts, which may take a few weeks. The advantage of the high-fat diet is that everyone has enough body fat for multi-hour hard rides, so refueling isn’t a concern.
If you eat a high-carb diet your metabolism adjusts to using glucose for energy. If you eat a high-fat diet your metabolism adjusts to using ketones.
Because your body specializes, you can’t switch back and forth in your daily diet and still ride well! For good recovery you also shouldn’t change your recovery nutrition from your daily nutrition. If you’re on a high-carb diet, then eat carbs after a ride. If you’re on a high-fat diet, then eat fat for recovery.
Eating a high fat diet will not help you lose weight! Assume your regular daily metabolism burns 2,000 calories. You’re on a high fat diet, you go for a slow-paced endurance ride and burn 1,000 calories of fat, for a total of 3,000 calories for the day. Over the 24-hour period you consume 3,000 calories so you’re in equilibrium: 3,000 calories out and 3,000 calories in. Your weight remains the same.
Now, assume you’re on a high-carb diet and instead of going for an endurance ride you do an intensity workout and burn 1,000 calories of glucose from carbs. Again, you consume 3,000 calories over 24 hours. You’re in equilibrium and your weight remains the same. Weight management is simply a function of calories in vs. calories burned.
As a retired pro told me, “In the spring ride more and eat less.” That is how to lose weight.
We’re each an experiment of one. A higher carb or a higher fat diet may be better for you. If you decide to try a higher fat diet, give it several weeks to see if it changes your performance.
Learn More About Cycling Training and Nutrition
I’m putting the finishing touches on a new bundle of five eArticles, including one brand new one – The Best of Coach Hughes: Making You a Better Cyclist. It will include:
1. How to Become a Better Cyclist: The Six Success Factors – A new article to be available only to riders who buy the bundle. Over 25 pages.
2. Your Best Season Ever, Part 1: A 32-page eArticle on how to plan and get the most out of your training published in 2015.
3. Intensity Training 2016: A 41-page eArticle with the latest information on how to use perceived exertion, a heart rate Monitor and a power meter to maximize training effectiveness
4. Optimal Recovery for Improved Performance: A 16-page eArticle with 10 different recovery techniques illustrated with 14 photos. Published in 2011.
5. Eat & Drink Like the Pros: A 15-page eArticle of nutritional insights from pro cycling teams. It contains a dozen recipes for you to make your own food and sports drinks. Published in 2011.
Buy The Best of Coach Hughes: Making You a Better Cyclist, totaling 130 pages.
Coach John Hughes earned coaching certifications from USA Cycling and the National Strength and Conditioning Association. John’s cycling career includes course records in the Boston-Montreal-Boston 1200-km randonnée and the Furnace Creek 508, a Race Across AMerica (RAAM) qualifier. He has ridden solo RAAM twice and is a 5-time finisher of the 1200-km Paris-Brest-Paris. He has written nearly 30 eBooks and eArticles on cycling training and nutrition, available in RBR’s eBookstore at Coach John Hughes. Click to read John's full bio.