Eating and Drinking on Gravel Rides

By Coach John Hughes

Nutrition for gravel rides is similar to nutrition for other endurance rides, with these differences:

1. Riding rough roads takes more energy per mile. One study on The Effect of Cycling-specific Vibrations on Neuromuscular Performance tested 30 trained cyclists. The study found “Oxygen consumption (+2.7%) and heart rate (+5%–7%) increased significantly in the presence of vibration. … Vibration is a full-body phenomenon. However, the impact of vibration on propulsion is limited as the main propulsive muscles at the thigh are not majorly affected. The demands on the cardiopulmonary and respiratory system increased slightly in the presence of vibration.”
2. Riding gravel uses more muscles than riding on the road, which also uses more energy per mile. You use your core to stabilize yourself on the rougher surface and you use your upper body to manage the bike. Yesterday by buddy John Elmblad and I climbed Shrine Pass (11,089′) in Colorado.  We rode up Vail Pass (10,666’) on pavement and continue up the rough gravel road to Shrine Pass. The difference in energy expenditure between pavement and gravel was obvious.
3. Tires for gravel are slightly heavier, stiffer than road tires and may take more energy.  Jan Heine has written an excellent column Are gravel bikes slower than road bikes? He concludes tires for gravel may or may not be slower than road tires, depending on the design of the tires.
4. Aid stations are farther apart. For example, Unbound Gravel 100 mile only has these: Mile 43.1 Water oasis – no food. Mile 64.1 Checkpoint with food – support crews allowed only at this checkpoint.
5. Aid stations may have limited choices. Club-sponsored road events often have fresh fruit, baked goods and even sandwiches in addition to sports drinks and bars. Gravel events often just have nutrition supplied by sponsors. Unbound Gravel’s partners include GU and The Feed.

Experiment of One

We’re each an experiment of one. I’ve been coaching for 40 years. I’m providing you what I know from nutrition science and working with my riders, which may or may not work for you. In advance of the event try to find out what food and drinks will be available at the checkpoints. If you don’t like these then you’ll need to carry more of your own supplies. On your training rides experiment with different foods and drinks. What are the best things for you to consume? Food and drink you like and that agree with your stomach so that you’re more likely to consume them. 

A Little Physiology

You are always metabolizing a combination of fat and glucose when you’re riding. Riding below your anaerobic threshold (AT), also called lactate threshold, about 50% of your energy is coming from glucose and 50% is coming from fat. Above your AT the major source is glucose although you are still burning fat. The harder you ride above AT the more glucose per minute you are burning. On a gravel ride you’ll be riding at an endurance pace below your AT.

Glucose is stored in the body as glycogen, which comes from carbs. Your body can store about 1,800 calories of glycogen. (1,400 in the muscles, 320 in the liver and 80 in your blood.) How much you store depends on your body size and your fitness. 

Your body has about 100,000 calories of energy stored as fat, an unlimited supply of fat.  Even the skinniest pro has enough body fat to fuel a long race.

Protein provides only about 5% of the energy for the working muscles, although it is important for rebuilding muscle damage after a ride.

Because your fat reserves are ample but your glycogen stores are not, eat carbs!

Approximate Calorie Needs While Riding

Many cycling computers estimate how many calories you are burning riding on the road based on your weight, speed and amount of climbing. If you don’t have a computer, use this table to guesstimate your burn rate. This assumes you are riding on pavement, on the flats, not drafting and on a calm day.

• 12 mph (19.3 km/h) burns 2.5 Cal / Lb. / Hr. (5.6 Cal / Kg / Hr.)
• 13 mph (20.9 km/h) burns 2.8 Cal / Lb. / Hr. (6.2 Cal / Kg / Hr.)
• 14 mph (22.5 km/h) burns 3.1 Cal / Lb. / Hr. (6.8 Cal / Kg / Hr.)
• 15 mph (24.1 km/h) burns 3.4 Cal / Lb. / Hr. (7.4 Cal / Kg / Hr.)
• 16 mph (25.7 km/h) burns 3.7 Cal / Lb. / Hr. (8.1 Cal / Kg / Hr.)
• 17 mph (27.4 km/h) burns 4.0 Cal / Lb. / Hr. (8.9 Cal / Kg / Hr.)
• 18 mph (29.0 km/h) burns 4.5 Cal / Lb. / Hr. (9.8 Cal / Kg / HR)
• 19 mph (30.6 km/h) burns 4.9 Cal / Lb. / Hr. (10.7 Cal / Kg / HR)
• 20 mph (32.2 km/h) burns 5.4 Cal / Lb. / Hr. (11.8 Cal / Kg / HR)

If a rider weighs 140 lbs. and is riding at 14 mph on pavement then the rider is burning 140 lbs X 3.1 Cal / lb. / hr., which calculates to 434 calories / hour. These are approximate figures.  This roadie is burning roughly 400 – 500 calories / hour.

As explained above riding on gravel takes more energy. The above study on the effect of vibration is the only quantitative study I could find on the increased energy cost on gravel. The data only relate to vibration, not bike handling and rolling resistance. For gravel assume you’re burning 10 – 15% more calories than on the road. However, you’re not riding as fast on gravel as on the road so your hourly burn rate is may be less than riding on the road.

The American College of Sports Medicine(ACSM) recommends consuming 25 to 60 grams of carbs (100 to 240 calories) per hour after the first hour of exercise depending on body size. Note the recommendation is for calories of carbs only.

The ACSM’s recommendation is good for rides up to about a half day; for longer duration rides start eating in the first hour and eat more. However, your digestive system can only process about 240 calories / hour of one type of carb, e.g., glucose, or sucrose or maltodextrin. You can digest up to about 360 calories per hour of multiple types of carbs.  Here are a few examples (I’m not recommending anything):

* GU, Vanilla Bean — 100 calories per packet, 100% carbs, both maltodextrin and fructose

* Hammergel, Apple-Cinnamon — 90 calories per packet, 100% carbs, only maltodextrin

* Clif Bar, Chocolate Brownie — 250 total calories, 172 calories of carbs (69% of total calories) from oats, rice syrup, cane syrup, chocolate and cocoa

* Hammer Bar, Oatmeal-Apple — 190 total calories, 124 calories of carbs (65% of total calories), mostly fructose from dates, dried apples and raisins plus oats.

* Honey Stinger, Organic Stinger Waffle — 160 calories, 88 calories of carbs (55% of total calories) from wheat, rice syrup, cane sugar and honey.

Hydration

Dehydration hurts performance, right? Not necessarily.

Pro stage racers ride so hard that their guts can’t absorb enough fluid to replace all that they are losing in sweat. Race rules also restrict when a rider can get a bottle toward the end of a stage. Although somewhat dehydrated, the pros sprint quite well!

For decades marathoners raced 26.2 miles in both cool and in hot conditions without drinking.

The average male’s body is 60% water; the average female’s is 50%. The typical athlete has another 10% water because glycogen is stored with water. Obviously, if we don’t replace this, we die. However, almost all of the heat-related deaths every summer are shut-ins living in homes with no air conditioning. Your body has about 2 quarts (liters) of free water in your intestines. You don’t even start to feel thirsty until you’ve lost 1.5 to 2 quarts of water!

We’ve all seen pictures of runners collapsing at the end of a marathon or triathlon. Must be because the runner is dehydrated, right? Wrong. When an athlete stops, the runner’s pulse and blood pressure fall significantly so that less blood gets to the brain and the runner faints.

Although pro cyclists routinely get somewhat dehydrated during races, we rarely read about cramps in the peloton. In lab experiments, dehydration has been shown not to cause cramps.

For more read my column on 12 Myths About Hydration.

What to do During the Event

Pre-hydrate. The week before your event check yourself for signs of dehydration:

1. Thirst. This is the most obvious and as noted above you’re already dehydrated before you feel thirsty.
2. Pinch and release the skin on the back of your hand or forearm. If your skin stays pinched for a few seconds instead of immediately becoming normal, then you probably need more fluids.
3. Urinating. If you’re not urinating every two or three hours you probably need more fluid. However, dark urine isn’t a sign of dehydration.
4. Mood swings. Studies suggest even mild dehydration could make you more irritable and even anxious.
5. Lightheadedness: If you feel dizzy after standing up, you are probably are dehydrated. You get dizzy or lightheaded when your brain isn’t getting enough blood. AS you get dehydrated the volume of your blood decreases lowering your blood pressure causing lightheadedness.

[New York Times 5 Signs You Might Be Dehydrated]

If you have any of these get more fluids until the signs go away. In addition to beverages, oranges, strawberries, watermelon and even lettuce are primarily water.

Another useful article is How Much Water Do You Actually Need from the New York Times.

Carbo-load. As noted above your body can only store about 1800 calories of glycogen from carbs. Before a big ride it’s critical to ensure your fuel tank is full of glycogen.  The week before your event increase the proportion of carbs in your diet:

• 70-75% of total calories from carbohydrate
• 15-20% of total calories from fat
• 10% of total calories from protein
• Your plate should be covered primarily with carbs. When you increase the carbs be careful not to also increase fats such as pasta sauces.

Carbo-loading also helps with hydration. With every gram of glycogen (from carbs) your body stores your body also stores three to four grams of water. This is why you gain weight when you carbo-load.

For more information see my column on Carbo-Loading for Endurance Athletes

Eat carbs during the ride. Your body has plenty fat to get you to the finish line but not enough glycogen. You can only carry a limited amount of food so carry carbs. The above list of gels and bars has the percentage of carbs per item. Real food often has a higher percentage of carbs. Here are a few examples:

• Banana, medium — about 110 total calories, 100 calories (91%) from carbs.
• Fig Newtons, 2 —about 110 total calories, 90 calories (82%) from carbs.
• Bagel, plain, 1 — about 290 total calories, 230 calories (79%) from carbs.
• Granola bar, average, 1 — about 115 total calories, 90 calories (78%) from carbs.

A nutrition label is required on every food product except fresh fruit. The label gives information per serving. Check what one serving is — it may be smaller than you usually eat. The label gives you total calories per serving and total grams of carbs per serving. One gram of carbs = 4 calories. For example, a 2.25” diameter (0.4 oz.) chocolate chip cookie has a total of 48 calories. It has 6.7 grams of carbs. 6.7 gm X 4 calories = 26.8 calories of carbs, only 55% of the total calories. The bananas, Fig Newtons, bagels and granola bars all have higher percentages of carbs and are better choices – as long as you like them!

Calorie King is an excellent resource to look up nutritional information for specific products.

Drink carbs during the ride. Sports drinks are another good source of calories. Although the serving sizes vary all of these have about the same calories per fluid ounce.

• Gatorade, 20 fl. oz. — 140 calories, all carbs
• Powerade, 12 fl. oz. bottle — 80 calories, all carbs
• Heed, 30g — 110 calories, all carbs.

Eat snacks. Because your body can only digest a limited number of carbs per hour it’s important to eat every hour. As you get tired it’ll be harder to remember to eat.  Set your watch or computer to beep every fifteen minutes — when it beeps eat! 

Easy to eat. You’ll primarily eat while you are riding so your food choices should be easy to unwrap and easy to eat.

Carrying Nutrition

You’ll need to carry more food and fluid because the aid stations are much father apart.  I’ll use REI’s products as examples.

• Hydration packs. Some only hold fluid bladders; others also have pocket(s) for food. The larger the pack the more you can carry; however, your shoulders and back may not be comfortable after a number of hours.
• Handlebar bags. Handlebar bags are great for accessibility. The larger bags put noticeably more weight over the front wheel and may change how your bike handles.
• Top tube bags are also very convenient. They have less carrying capacity than most handlebar bags; however, because the weight is on the frame they don’t affect bike handling
• Frame bags fit under your top tube. They aren’t as convenient while you’re riding. Because the weight is also on the frame they don’t affect bike handling.
• Seat packs these range from 0.8 L up to 17 L! One of them has a pocket to carry another water bottle. The larger the bag the more it will affect bike handling.

Distributing the weight is important so you don’t affect how your bike handles. For example, instead of a large seat bag, get a smaller one and a handlebar or top tube bag so your nutrition is handy. Instead of a very large hydration pack you could get a smaller one that’s more comfortable and also carry a couple of screw top bottles in your bags.

To get used to how your bike handles use your bags on your training rides with everything you plan to carry on the event.

Related columns

• What’s the Best Food for Cycling
• 14 Nutrition Tips for Endurance Riders
• Preventing Bonking and Hitting the Wall, part 1
• Preventing Bonking with Daily Nutrition
• What Should a Beginning Cyclist Eat and Drink, part 1
• What Should a Beginning Cyclist Eat and Drink, part 2
• Recovery Nutrition
• Bicycling in the Heat 101
• How to Ride Safely in the Summer Heat
• Why “Drink Before You’re Thirsty” May Be Dangerous
• What Is the Best Electrolyte Supplement
• What Electrolytes Do You Really Need

Nutrition for 100K and Beyond. In this eBook I give you the principles and recommendations for eating before, during and after a ride. I wrote the Nutrition for 100K and Beyond for roadies — it also applies to gravel riders. Although written for rides of 100K and farther, all riders can learn from it. I explain how to estimate about how many calories per hour you burn. I describe what to consume for endurance, tempo and intensity rides. I explain the difference between simple and complex carbohydrates and describe the glycemic index, which measures how fast your blood sugar rides after eating or drinking a specific item. I also discuss hydration and electrolytes.  I conclude by discussing what you should eat every day to ride your best.  My 17-page Nutrition for 100K and Beyond is just $4.99.

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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 over 40 eBooks and eArticles on cycling training and nutrition, available in RBR’s eBookstore at Coach John Hughes. Click to read John’s full bio.