When do you fuel? How much do you eat? What are the best products to use?
We have noticed over the last 4 years that many runners tend to overestimate how much they need, causing them to overeat during the day and gain unwanted weight during the season. And eating too much during training can trigger a multitude of stomach issues (e.g., nausea, diarrhea, vomiting, side stitches, sloshing) and ultimately hinder your performance.
Below is a step-by-step guide to help you determine your total calorie needs during training runs and your target calorie replacement needs based on your race pace.
Determining your total calorie needs
Step 1: Determine running calorie expenditure per mile (0.63 x body weight in pounds)
Step 2: Determine goal race pace or how many miles per hour you'll cover (Example: An eight-minute miler will cover 7.5 miles/hour)
Step 3: Calculate hourly expenditure based on goal race pace (Example: An eight-minute miler would multiply 7.5 by the figure from step 1)
Step 4: Determine hourly calorie replacement needs (0.3 x the figure from step 3. Note: Research shows runners can physically absorb about 30 percent of what they expend.)
Real-life Example: Panther is a 160-pound marathoner preparing for the AT&T Marathon with a goal of breaking the three-hour mark. He's had issues with premature muscle fatigue and cramping during previous marathons, which has led him to seek nutritional advice for race-day fueling. We used the guidelines specified above to help calculate and devise the perfect nutrition plan for his needs.
Step 1: Panther's calorie burn each mile (0.63 x 160 lbs = 100.8 calories/mile)
Step 2: Panther's goal marathon goal is to break three hours means 6:50 per mile (he'll be running 8.78 miles per hour)
Step 3: Panther's hourly expenditure based on his goal marathon pace (8.78 miles per hour x 100.8 calories per mile = 885.02 calories burned per hour)
Step 4: Goal calorie replacement after 60 minutes of racing (0.3 x 885.02 calories = 265 calories/hour)
Step 5: Panther's calorie replacement (The first 60 minutes of the marathon, Panther plans to use the course-provided water at aid stations to maintain hydration. After 90 minutes, Panther's goal is to consume approximately 265 calories per hour until he finishes, which means he'll need approximately 530 calories)
What products do you use?
This is really when the debate begins. I am also confident that I can not answer that for you. You need to try products in order to figure out which you like and which ones sit best in your stomach. There are so many good products available; it is your job to figure out which one you like. Look back at your training log, especially at the LAB runs, to see what products you used on your successful runs. Review the 20 Miler with an eye to how products worked for you and adjust accordingly (you may want to tweak and try some things on the next few long runs). It will be up to you to carry anything you need at the marathon, other than the provided Powerade & water at each aid station. Think of every long run from now until taper time as an opportunity to fine tune your nutritional strategy.
Eat before you run.
While runners can get away with not eating before moderate-intensity training bouts lasting less than an hour, performance tends to decline if food is neglected prior to exercise lasting longer than an hour (especially if the exercise occurs in the morning after a prolonged fasting state). The food consumed prior to longer training bouts will restock liver glycogen stores, helping to stabilize energy levels during the initial stages of training and also increasing fuel efficiency due to sparing of muscle glycogen. Runners who fail to fuel prior to long training will “bonk” and start depleting their muscle glycogen stores prematurely and most likely fall victim to the performance declining “wall.”
A general rule: for every hour prior to exercise, athletes should consume about 2 calories per pound of lean body weight, aiming at 1 gram of protein for every 4 grams of low-to-moderate glycemic index carbohydrate.
You might not know what you lean body mass is. The average female is about 24% body fat, while the average male is about 15% body fat. (Panther, therefore, would probably be 145 pounds of lean body weight, so he should consume 290 calories for breakfast.)
If you don’t know, I suggest that you take in somewhere between 200 - 300 calories before you get to the run. Possible foods include peanut butter on a bagel, oatmeal, banana, a gel, a Clif bar. These will replace the carbohydrates you burned while sleeping. Drink about 8 ounces of water with your food. If you’ve already tried this before the DCS races, you should have some what of an idea of what works for you. Again, go back to your training log and review successful runs (and the bad ones, as we sometimes learn more from a failure than a success).
Without a solid nutrition and hydration plan, you will not be able to reach the marathon finish line successfully. You can see that Panther needs 400 calories for his sub-3 hour finish. What do you need?
The last part: hydration.
Dehydration (loss of fluids) can have a profound effect on marathon performance. Runners who blow by those initial marathon water stops tend to be reeled in during the later stages of the race as the onset of “thirst” can trigger an approximate 15% decline in their performance capability. Besides thirst, symptoms of dehydration include muscle cramping, muscle fatigue, nausea, vomiting, diarrhea, and chills.
In the most severe cases of dehydration, the body’s core temperature may increase to 108oF, which, if prolonged, will lead to kidney failure and death. To avoid severe cases of dehydration, runners should aim at replacing 0.5-1 liter of fluid each hour during runs, implementing an electrolyte-rich beverage (e.g. sports drink) after 60 minutes of running.
A sports drink should contain the following approximate concentration of electrolytes per 8-12 fluid ounce serving: Sodium 150-250 mg, Chloride 45-75 mg, Potassium 50-80 mg, Magnesium 20-30 mg, Calcium, 10-15 mg. Those vulnerable to muscle cramping will also benefit from ingesting a sodium-rich food (e.g., salt bagel) or beverage (sports drink) as part of the pre-race nutritional plan.
The most important way to combat this is by coming to the workout or race hydrated. If you are dehydrated when you show up you are not going to catch up during exercise. It takes 2 weeks to get fully hydrated. Some of us think that drinking well a couple of days before the big race will be fine, but this is not completely true. It takes time for the body to fully absorb and utilize the fluid and come to a new equilibrium with a fully hydrated system.