Nutritional Fueling for an Ironman

By Dave Scott

Nutritionally speaking, we didn't know a whole lot in the early 1980s. Each athlete would seemingly load their water bottles with a unique, home-brewed concoction. The drinks were usually extraordinarily sludge-like with a slight brownish tint. I had heard that these "loaded caloric bombs" often exceeded 1500 calories per water bottle.

The common recipe for optimal nutrition was a combination of ground or pureed candy bars, honey and dextrose tablets blended with the chef's favorite beverage. Its not that I was smarter, I just didn't like candy bars, and I thought honey and Coca-Cola didn't sound terribly appetizing.

I took a simplified track and drank water plus Exceed, one of the first fuel-replacement drinks tailored to endurance athletes. In the 1980 Kona Ironman, athletes were required to have an endurance support vehicle, which upon a simple hand gesture, provided whatever fuel or fluid you desired. I loaded up my team and station wagon with a few baked potatoes, several bunches of bananas and lots of water. Bars, gels, sodium intake, and protein—we didn't know a thing about those topics, nor were they available.

Survival was the fueling ticket for the early races. I tended to eat liberally and never had stomach or prolonged fatigue issues. My competitors, who selected the caloric bomb drinks, were on the side of the road numerous times throughout the later stages of the bike, and the run was catastrophic, to say the least.

Natural Energy Lab Rats

As we moved through the early '80s, the preparation of Ironman fueling became more sophisticated—or at least we thought so. I vividly remember Kenny Glah carefully dicing and stacking about 12 bars on his top tube. These were displayed like a fine chef's dessert tray. However, at the end of the leg, the bars had been sprayed with sweat, coated with fuel-replacement drink and baked in the Kona sun. The end result was a slimy, dripping glob of disaster. With all respect to Kenny, he was a tenacious competitor, despite his food selection, preparation and the final display.

My secondary source of fuel for two Ironman race was dried 19 Calimyrna figs. I was looking for a fuel that could be packed in my jersey, contained lots of calories and was palatable after several heated hours of competition. Figs seemed golden until I realized that the high fructose and off-the-chart fiber content could present problems—big problems. I was lucky, but fellow competitors who followed my nutritional model experienced gastrointestinal (GI) distress of catastrophic proportions.

Despite the athletic prowess of the top men and women, we honestly did not know a lot about fueling. We trained hard, raced like demons and crossed our fingers that we did not have stomach problems. Fortunately, our learning curve evolved rapidly, and by the late '80s we had a more precise diet for total-fluid intake, types of calories and simply what worked during an Ironman.

Fueling for the Finish Line

While many Kona-bound triathletes are particular eaters during training, it is vital that proper nutrition is maintained in the days leading up to the race. Maintaining calories, priming the body for competition and reducing the risk of GI distress can be accomplished by following these guidelines.

Don't consume electrolyte drinks the day before—your electrolyte levels will be fine due to tapering and dietary intake.

Dinner the night before should allow a 10-hour transit time before your race-morning breakfast.

Eat two to 2.5 hours before the gun goes off.

Eat gluten-free products on race morning.

Your race-day breakfast should be on the lighter side based on your total body weight. I would stick with a safe range of 65 to 70 percent of total intake as carbohydrates. For example, if you weigh 155 pounds (70 kilograms), fuel up with 1.0 grams per kilogram: 1.0 x 70 = 70 grams of carbohydrates. 4 calories x 70 = 280 carbohydrate calories. The remaining 30 to 35 percent would be split between protein and fat calories. Obviously, the total is relatively small.

Don't eat anything after your race-morning breakfast with the exception of consuming four to eight ounces of electrolyte drink 10 minutes before the gun goes off.

This is the big one: Don't eat or drink until your breathing rate, heart rate and sweat rate have stabilized on the bike. This should be a 10- to 20-minute period on the bike before introducing small sips of electrolyte drink. The number one factor in GI distress is consuming too much too soon. Keep your total caloric intake at 25 to 40 percent less than usual during the first hour on the bike. For each remaining hour, maintain a steady caloric intake based on your body weight, intensity and duration of the race.

When replacing calories, only consume about 25- to 33-percent of the total calories burned per hour.
Athletes that err on the lighter side of fueling generally have smoother sailing when the gun goes off. Eating mountains of calories on the bike is relatively easy, but as the race progresses and water is drawn to the gut, your legs can feel catatonic on the run and will begin to remind of your excessive mistake.