Fueling on the Bike

Now that I have begun to do some longer rides, I have to consider how to fuel myself before, during and after them. This is foreign territory to me, as I am used to fueling myself for long runs which are usually not longer than 2-3 hours. My fuel strategy for long runs is to have 100 calories every 45 minutes or so, starting 45 minutes into the run. For example, during a 10 mile (1 1/2 hours) run I will most likely only have 100 calories, and for a 18 mile run (about 3 hours) I’ll have 350-400.

Confusion About Calories Burned:

To me, biking feels easier than running, so it seems that you would burn fewer calories and therefore need fewer. I went to the Internet to research my theory, I came up with some very mixed results. First, I have been told by a dietitian that a 150 pound person burns 100 calories/mile while running. Since I weigh less than this, I usually estimate that I burn about 90 calories per mile. Since I can run about 6.5 miles in an hour, I’d burn 585 calories per hour running at a 9 min/mile pace. However, according to the Self Nutrition Calculator which takes into account my age, height,and weight, running at this speed for one hour burns 862 calories and biking for 1 hour at 14-16 mph burns 776 calories, which seems high to me. On the other side of the spectrum, the Activity-Calorie Calculator on Powerbar.com says that someone my weight (the only factor considered) burns only 311 calories per hour while biking 14-16 mph and 389 calories per hour while running a 9 min/mile.

Those are some BIG discrepancies in calories burned. Now I am even more confused! Do I burn closer to 800 or 300 calories per hour while biking? I definitely think it’s closer to 300, although this number sounds a bit low. Obviously there are many factors to consider when calculating calories burned, including the weather, wind and terrain (hills, etc). I would say that a good estimate of an “easy” ride for me burns 350-400 calories/hour whereas a hard ride probably burns more like 400-500 calories an hour.

Fueling for Speed

Although I may burn less calories while biking than running, the goal for fueling on the bike during a race is to consume enough substance to make up for the calories used on the swim and also prepare the body for the upcoming run. How many calories you need is variable depending on your sex, height, weight, the weather and other factors. Therefore, it’s critical to practice nutrition before race day so that there aren’t any surprises. Unfortunately, one of the biggest reasons for a DNF (do not finish) at the Ironman is gastrointestinal distress, rather than injury or fatigue. People literally end their day on the toilet at Ironman. The main reason for GI distress is either 1) not enough fuel or 2) too much fuel. See why it’s important to practice?

My longest rides to date so far have been about 3 1/2 hours. I’ve recently learned that I am not taking in nearly enough calories on these rides. Each time we’ve ridden this course (3 times so far!), I’ve drank 24 ounces of water mixed with 135 calories of Cytomax ( 1 1/2 scoops) and had two Gus. If you can do the math, that’s only 335 calories for a 3 1/2 hour ride. I’ve finished each ride feeling pretty wiped out and tired, certainly not energetic enough to run a 10k or half marathon (or even worse, a marathon!). My logic in only consuming this many calories was that I didn’t see the point in eating much more since I didn’t have to run afterward. However, if I’m honest with myself, my energy levels definitely decrease toward the end of the ride, and if I plan to increase my mileage, I’m going to need more calories to get me through. Likely, my performance is suffering due to undernutrition.

Trial and Error – How Many Calories Should I Take In?

From what I’ve read, there is no hard and fast rule for calorie consumption during races. That is why it’s imperative to practice your nutrition on the training rides. Although you probably don’t need quite as many calories on a 100 mile training ride as you would during the 112 mile bike portion of the race, you should practice consuming as much as you would on race day so that you know that your body can handle it. For example, one of the bloggers that I follow, Maria (RunningALife), has found that in a race, 100 calories per hour on the bike is too little and 200 calories is too much. Therefore, she will consume about 150-180 calories/hour during races and during training rides. She doesn’t take all of these calories at once, but rather spreads them out in about 15 minute increments and gets them from both liquids and from solids. That works for her, but would it work for me? Since I am taller and weigh more than Maria, I will probably need more calories. I plan to try 180- 200 calories an hour to start, and then move from there. I’ll know I’ve consumed too few if I lack energy during my ride and I’ll know I went too far if I have bloating or cramping.

Trial and Error – What Kind of Calories Work For Me?

What type of fuel is another issue. Most triathletes get their calories from a mix of sports drink, gels and solid food. The sports drink provides easy calories and also electrolytes which are essential when racing long distances and even more crucial at temperates over 65 degrees. Gels and blocks are a popular source of race fuel since they are easily digested, (many) contain performance boosting caffeine, and they have been formulated for endurance sports. However, since I’ll be on the bike for 7-8 hours on Ironman race day, I’ll most likely want to eat some solid food as well. I can’t imagine being satisfied sitting at my desk eating Gu and Cytomax all day, so I doubt that I’ll be able to fill the void with these things alone while working out for 8 hours. Although it is difficult to consume solid food during high intensity exercise, the Ironman bike portion should be raced at a moderate pace that allows your body to have enough spare energy to digest solid foods in your stomach.

Some solid foods that I plan to incorporate into my long rides include bananas, Cliff bars, and peanut butter banana sandwiches. I may also toy with some salty foods like pretzels once I start getting into really long rides, especially in the spring when it starts warming up again. Pretzels and other salty foods are usually served at aid stations during the Ironman to ensure that athletes don’t deplete salt stores and cramp.

Writing It All Down

After our first 40 mile group ride, one of the women there that had just completed Couer D’Alene this year gave us some advice for nutrition on the bike. She suggested that we keep track of every ride we go on and write down the distance, difficultly level, how we felt and what we ate. We should record every single thing we ate so that we can go back and look it over and compare what/when we ate with how we felt and how we performed. I plan to start doing this so that when I show up to the start line on June 24 there is no question in my mind as to what my stomach can and can’t handle and what will give me enough energy to finish the distance.

Practice makes perfect!

Side Note – When looking for the above photo of the bike full of race day nutrition, I found a pretty interesting blog by an Ironman champion who argues that you don’t need much fuel AT ALL for an Ironman and that most GI distress is a result of over-consumption. http://www.m2rev.com/articles/m2_training_concepts/ironman_fueling.html