Nutrition/Fueling At The End Of A 100 Miler: Andy Holak, Karl King and Tony Krupicka

Posted on the Ultralist:
On Behalf Of Andy Holak
Sent: Wednesday, December 06, 2006 3:16 PM

Subject: Nutrition/Fueling at the End of a 100 miler

All this talk about how many calories per hour we can/should take in during a 100 miler has me pondering a quote I saw from Anton Krupicka in the October 2006 Ultrarunning magazine. In response to his nutrition plan for Leadville, he mentioned toward the end of this section that, “The last two hours in from Mayqueen I basically stopped eating and drinking. I was afraid of my stomach becoming upset again, plus, especially the last hour or so, I became very focused on just running fast and getting to the finish. Not eating at that stage didn’t seem to affect me too adversely.”

I found this quote interesting in that I have also experienced this in 100 milers. Most recently at Western States this year where I had all kinds of trouble in the canyons and ended up on cots in both Michigan Bluff and Foresthill for what seemed like hours (literally, I guess it was a couple
of hours:-). I had trouble keeping anything at all down even water. During the last 20 miles I was very focused on finishing, and ended up running pretty fast to the finish (passing close to 40 runners over the last 20 miles or so). Over the last 20 miles I didn’t eat much at all and didn’t
drink much either. It seemed like I didn’t really need any nutrition at that point, and I felt I could run strongly without drinking much either. This same experience occurred during Western States
in 2002 as well, and somewhat during Leadville in 2004.

Is there a mechanism behind this? Has my body converted over to burning fat so effectively at this point that I no longer really need to take in any other calories (or very few calories anyway)? Can you focus your mind so much at the task at hand when you’re running faster or more focused that you don’t need to take in the calories, or your mind tells you that your not hungry or thirsty at all?

The fact that I was able to run as fast the last 20 miles at Western States that I did on the amount of calories and fluid that I consumed still baffles me (and I think it might also still baffle my
pacer;-). It would be interesting to hear others stories about their food and fluid requirements at the end of 100 milers or even 50 milers.

Andy Holak

Karl King wrote:


Like many mysterious affects found during ultras, these are from the endocrine system. What’s going on is that

A) your body is pumping out a lot of cortisol, which allows you to draw energy stores from your own body ( fat and protein). Instead of getting calories from external food sources, you are consuming your own body to get the calories for running.

If you didn’t feel the need to drink much, you may have over-consumed water earlier in the race and were living off water already stored in the body some hours earlier. This especially likely if your digestion was not going well earlier.

B) the endocrine reactions can strongly suppress appetite and thirst, making you think you are not hungry or thirsty.

These affects are part of your body’s survival mechanism. You are drawing on your body’s stores in a perceived emergency.
This can work well for a few hours, but at some point you will run out of reserves and experience a major crash. The hope is that you cross the finish line before that happens.

More information on endocrine effects in ultras can be read at

Karl King

From: Tony Krupicka
Subject: Re: Nutrition/Fueling at the End of a 100 miler


It sounds like Karl has pretty much nailed it physiologically. I remember being a little surprised myself the last 2 hours of Leadville–I virtually didn’t drink at all and had just 1 gel at the bottom of the Boulevard because I figured it would really suck if I crashed in the last 3 miles. I remember being really hungry at that point but not lacking in energy, which is kind of weird.

However, I think the psychological aspect is what was playing the biggest role for me. My pacer and I were really hittin’ it the last hour or so of the race and all I cared about was running as fast as possible because I realized that a sub-17hr time was suddenly possible again. We were very focused. Curiously, I also remember feeling really really surprisingly great the last mile or so through town—probably just adrenaline, though.

What still puzzles me is why I felt so terrible on top of Sugarloaf (~80 miles)on the way back, didn’t change anything in my fueling, and suddenly bounced back in a big way after Mayqueen. Instinctively, I feel like it was related to nutrition, but I didn’t change anything to start feeling better. I just started feeling better. But, that’s probably not that unusual for a 100 miler.

Tony The home of multiday running news and events.

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