Friday, October 3, 2014

Marathon Nutrition Strategy

One of the challenging aspects about the marathon is how to take in energy as you're running. This is important, because as Sara Latta's article details, most runners only have ~2,000 calories worth of glycogen stored in the muscles and liver, enough to get you to about mile 20. Once you deplete your glycogen reserves, you hit the Wall, where your body moves from burning glucose to burning fat, a much less efficient energy source. Latta writes:
"...burning fatty acids requires plentiful oxygen, so as fatty acid metabolism increases, your heart must work harder to pump more oxygen-carrying blood to the muscles. It may be difficult or impossible to maintain your pace, especially if you've lost enough water through sweat to become even slightly dehydrated (this causes your blood to become thicker and therefore harder to pump). ”
Sounds unpleasant! And it is - I've been there. Your limbs feel heavy and the mind becomes stagnant as the body focuses its energy elsewhere. So the trick is to take in enough glucose during the run to prevent or delay this turnover as long as possible. As someone that has a tricky stomach, this has been a challenge for me. How to best replenish my reserves as I run without sparking GI?

I've tried a few things over the years. These include:

  1. Acceleraide. Typically, I've drank the Orange flavor in my hand-held, but have also used other other sports drinks like Gatorade, etc. This appears to be effective, but I've encountered two issues with these sports drinks:  
    • Sweet. After a while, the thought of drinking more flavored drink is just nauseating – I just want water! Wish there was a way to carry just a shot or two with me.
    • Sour stomach. All of the carbs in the liquid doesn't always sit well.
  2. Gels. These are the most efficient method for immediate energy that I know of. I've used a number of different flavors and styles, but have mainly stuck with GUs. My issues with them are:
    • Flavor. These can range from horrible (Salted Watermelon!) to excellent (Salted Caramel!)
    • Caffeine. While at times it’s nice to have this added energy, caffeine can upset my stomach, especially on a relatively empty stomach on early morning runs. 
    • Too quick? At times, the energy hits me so quickly I sometimes feel shaky or jittery.
  3. Chews. My favorite. I find that the chews are a good balance of energy and slower digestion. My only issue here is that they’re very sticky and bulky, so not always easy to carry around. 

My tactic will be to rely mainly on chews and water. While I’m going to carry a GU or two with me, in case I need big boost of glucose for the later stages of the race, i'm going to avoid it if I can.

What do you think? What worked for you? Send along any advice you have in the comments.

Related Posts:
Don't Drive the Boat: My Nutrition Strategy for TNF 50 DC
To Supplement or Not to Supplement

1 comment:

  1. I actually really like the salted watermelon gu. The extra salt and the slightly herbal flavor make it feel less sweet than other gu varieties.