Marathon Nutrition

It’s Derby Festival in Louisville, KY now.  And that means all sorts of fun activities for the family and tourists that come to this great city over the next couple weeks.  It all starts off with Thunder Over Louisville, and before finishing with the infamous Kentucky Derby there are several of family friendly events such as parades, hot air balloon shows, concerts, the chow wagon (full of carnival food such as elephant ears and corn dogs), and several other activities.  The one that attracts one of the biggest crowds is the Derby Festival mini and full marathon.  About 17,000 athletes run in the mini and full marathon, and then add all the family and friends lined along the course and the number probably triples.  This coming weekend, I will be taking on the full marathon.  It will be my third stand-alone marathon that I’ve run.  I’m looking forward to running the streets of my hometown and feeding off the local support.  But, just with any race distance longer than 90 minutes, nutrition is key.  It can make or break the race.  The longer the race, the more important in-race nutrition become more important.  A marathon is no different.

So how does one fuel for a marathon race.  There are several schools of thought, but they all boil down to taking into consideration how much someone weighs, how fast they run, and their goal time.  Of course, one will never be able to completely replace the amount of calories they are burning at an equal rate.  The key is damage control with adequate caloric intake and pacing.  The formula that I’m going to present isn’t perfect because it can’t take into account a person’s running economy.  For example, two people weighing the same amount may not run with the same efficiency at their marathon race pace.  One of them may bound more (up and down movement) or possibly over stride causing the brakes to be put on slightly with every step.  That being said, it should give an athlete a rough idea of how many calories to consume during their marathon race.

Step 1: Determine running calorie expenditure per mile
0.63 x body weight (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.)

Here’s an example:  A 175 pound athlete wants to run a 3.5 hour marathon.  To determine the amount of calories needed to complete the race this athlete would start calculating his caloric needs after 90 minutes into the run since he/she should have eaten an adquate enough breakfast to fuel his body for this portion of the race.  The athlete would take 0.63 x 175 to figure out how many calories per mile they will burn.  It comes out to about 110 cals/mile.  Since he’s wanting to run a 3:30 marathon, that comes out to an average pace of just under 7.5 miles/hour.  So multiply 110 calories by 7.5 to get your cal/hr burned.  That comes out to about 825 cal/hr.  Since we can only absorb about 30% of the calories we burn while exercising, multiply 825 by 0.3 and the hourly requirement for after 90 minutes til the end would be about 250 calories/hour.  So for the final two hours of racing, this athlete would need to consume about 500 calories in order to give their body the correct amount of calories to make it through this race.

After figuring out my goal time, weight, and pace, I will need to consume about 300 calories per hour for the final 1:10 of my race.  However, I’m planning on taking some calories in about 35 minutes in and again at the 1 hour mark.  I plan on using NAPALM by Infinit for my calorie intake during the race.  a 6 ounce flask will carry 300 calories.  So if I supplement with some one course nutrition to get some additional calories, I should be fine.

Be sure to supplement with water and electrolytes if needed if it’s going to be hot.