Sunday, January 24, 2010

Energy Storage for Long Hikes

I'll probably repeatedly go over this topic. Right now I'm going to repost a discussion I added to this thread.

For nutrition, the general trend to follow is, the harder and longer you are hiking, the more simple carbs you need to be eating. This goes for any endurance activity.

The higher the intensity, the larger % you are burning energy from your muscle glycogen stores. When these run out, you will hit the "wall" as well known in marathon runs for example. You simply have to slow down when burning energy from fat.

So the key is to stop those glycogen reserves from running out. How do we do this? Carbs. Simple carbs. Sugar. Bread. These substances (foods with high Glycemic Index ratings) are the best for the same reason they are looked down upon when eating while sedentary: They will be absorbed into the blood stream very quickly.

Carbs with fiber take longer to breakdown (and may cause stomach issues), and fat and protein have to go through other chemical reactions before getting into form for usable energy.

Obviously, I'm talking about extreme case here. But since this thread was based on the idea of a "death march", trying such a hike would certainly need to follow this mantra. I think that's where AlanK's classic "thank god for GU" came from while doing some very strenuous hike. GU is all simple sugar. Cyclists, marathoners, etc... consume this sort of thing during races. Not fat and protein, or even carbs with a lot of fiber.

When I learned how to apply this, I was able to work out very intensely 4 days a week, with my hikes considered a "moderate" workout. 2 rest days, and I don't fatigue, because I make sure I recover properly by eating carbs after working out.

That said, I don't really do this on hikes. I mix a sandwich, jerky, cliff bar, trail mix, etc... (things I like!). I can go 6000 ft without eating and not be affected.

But when I did cactus to clouds (~11000 ft gain), I ate a decent amount during the hike, but not a lot of carbs, and I started 'hitting the wall' the last 1000 ft. In that case, it's good to have the knowledge that to be successful with those extreme hikes, carry a few French baguettes with you!


  1. This is great stuff, thanks. I'm in the process of altering my diet a bit for longer hikes and workouts. I'm constantly bumping my head against that pseudo-mystical place called the "wall".

  2. Weight loss guru Covert Bailey talks about simple carbs being the "kindling" that gets fat to burn. You only have a limited supply of muscular glycogen so it's important to keep in your aerobic zone (don't feel the burn!) so that you keep burning fat.

    Even with that, I find somewhere around 11,000 feet (for my sea-level self) that fats and protein just don't digest well and I need almost all carbs. Nuts, etc. seem to suck oxygen out of my muscles as they digest.

  3. @brian: having optimal glycogen storage will definitely help fight the "wall". most of that loading needs to be done the days before the hike, and then sustain during as discussed above. of course, training will also have a big part in that (there will certainly be a post on that)

    @jim: yes the body needs to be burning the optimal ratio of carbs / fat for a given duration of exercise. basically, you you want to time it to just exhaust your glycogen at the very end (if going for pace), or slower. if you are going at too high of a ratio, the glycogen storage will deplete early and you hit the "wall"

  4. One of my favorite things to do when climbing fourteeners in Colorado is to fill my pockets with gummy bears and pretzels. I start munching on those usually in the first couple of miles and eat a couple every half hour or so. That gets me to the top oh and plenty of water, of course.