Sunday, May 23, 2010

Bring on the Frosting! Or, Can You Run Your Ultra on Gels Alone?

I've been thinking a lot about on-the-run nutrition lately. Now in the throes of training for a 50-mile race, I troll the ultrarunning listservs and message boards somewhat obsessively for solid information on what people eat during an ultra, and - perhaps more importantly - how they keep it down.

Today's post comes as a result of a challenging training run yesterday: a run during which I truly succumbed to the kind of nausea and discomfort I hope never to experience in a race. Recent weeks have found me running frequently with my friend Sarah, an experienced ultramarathoner whose race resume includes a 100k finish at one of the toughest races out there: the H.U.R.T. 100, and who is currently training for a 100-miler coming up in a few weeks.

Sarah is tough. She's one of those natural runners who climbs steep inclines like they're rolling hills, and sustains an easy gait over almost incomprehensible distances - all with a smile on her face. But I'm starting to think one of the toughest things about Sarah is her stomach. You see, Sarah eats real food on the run, and when I try the same thing I seem to just get sick. On yesterday's training run, I could stomach mini "sandwiches" of saltines & peanut butter for about the first 14 miles, but after that they just wouldn't go down. Same is true of the mashed potatoes I tried to eat a week or two ago - they actually tasted ok going down, but running after having eaten them I started to feel a little "off."

All this got me thinking: Is it truly necessary to eat solid food on the run?

In my longest race to date, the Mt. Disappointment 50k, downing a GU every 30 minutes kept me from bonking, and while I certainly set no speed records that day, I finished the race feeling strong. Friends and family members thought it was funny I'd run 31 miles eating nothing but "frosting," but hey - it worked for me. Might I be able to use the same strategy for longer races?

Some minimal online research brought me to this article in UltraRunning magazine by Marin County sports nutritionist (and runner) Sunny Blende. After explaining that we can't just eat simple sugars on the run (the osmolality of our body fluids means that too-concentrated sugar solutions only lead to dehydration and cramping), Blende goes on to discuss the sports-nutrition advantages of maltodextrin, a complex carbohydrate (and the main ingredient in my beloved GU.)

In essence, because maltodextrin is a glucose polymer (and not a simple sugar) the body can absorb it readily in a 15 - 20 percent solution (rather than the 6 - 8 percent concentration for simple sugars), so the athlete can consume close to three times as many calories from maltodextrin as from simple sugars, while absorbing the GU at roughly the same rate as normal body fluids.

Blende closed her article with this paragraph, which I'll quote directly here, since for me, this is the part where the clouds parted and I could hear the angels start to sing:
Scientific studies show that complex carbohydrates are the fuel of choice for the ultrarunner. The gels offer an advantage by providing more calories per hour than sports drinks and by being easier to absorb than sports bars or solid food. For the back-of-the-pack runners who will be on the trail for many more hours than the elite runners, this can translate into more energy without going into a caloric deficit state. For the lead pack runners who are pushing themselves at a very high intensity (above 90 percent), the advantage can be less stomach distress and more calories can be absorbed for more energy. For those who are just using the ultra as a training run or are taking it easy, go ahead and enjoy the smorgasbord at the buffet table. But if you want to have an even better time, try some complex carbohydrates and watch the simple sugars.

In ultrarunning, we are all an experiment of one. Might I be able to finish my 50-miler this summer on GU alone? I guess we'll see. Some evidence indicates that may be enough, but at the same time, running with Sarah has made me more curious about solid fuels, too. I'm sure to continue experimenting with my nutrition plan throughout the summer until I find what works best for me.

In the meantime, for my 50k race two weeks from now, I'm strongly inclined to implement the plan that's worked for me in the past: a GU every 30 minutes, supplemented by some electrolyte caps as needed.

See you on the trail - and bring on the frosting!
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