Last weekend, I embarked on a 30-mile 3-day, 2-night backpacking trip in the Olympic National Park with a group of friends, an activity that’s becoming a yearly tradition. Not only is it a test of physical activity, but also it is a welcomed break from the “civilized” world.
People are often curious about what I eat on an adventure like this and are then amazed at how little food I actually consume on the trail, perhaps imagining that a physically demanding activity like backpacking would drive one to have serious hunger.
Trail Food
It’s a verycommon phenomenon for backpackers to experience a surprising lack of hunger. Knowing this from my previous experiences, I packed very little food, which amounted to:
- ~1 lb beef jerky
- 1 tin sardines
- 2 1.5-oz packets of dehydrated liver crisps
This amount of food was more than enough for me to power through 30 miles, though substantially less than I would normally eat over 3 days.
Fat Adaptation
The key explanation for how this is possible is the concept of fat adaptation. Going into the hike, my body was poised to be in fat-burning mode, thanks to my preparation. For 3 weeks prior to the hike, I consumed basically zero carbohydrates, thereby forcing my body to efficiently utilize fat as fuel. For the typical carb-burner, it often takes several weeks, e.g. 5-6 weeks, to get fat-adapted.
Glucose burners
In contrast, 99% of the population is dependent on glucose (carbohydrates) for energy. Though their bodies are capable of utilizing fat as an energy source, they’re terrible at doing so. That’s because they have maintained lifestyles that provide a near-constant supply of carbohydrates. When glucose is plentiful, the body will metabolize glucose and will never have to dip into the fat stores.
Bonking
Being dependent on glucose can indeed be a bad thing. Consider, for example, what happens to marathon runners who “hit the wall”, or “bonk”. Essentially what’s happening is that they are depleting their glucose and glycogen stores and then their bodies are incapable of using fat as the energy source. That’s like a tanker truck carrying tens of thousands of gallons of fuel that runs out of gas. There’s an enormous amount of fuel available, but it’s not easily accessible.
Instead, you want to be more like an efficient hybrid fuel car. When the battery power (glucose) is depleted, you efficiently tap into the fuel reserve (fat) to continue performing.
Takeaway
Back to the backpacking trip . . . it doesn’t take long for backpackers to enter into a state of ketosis, where their bodies are burning fat. Once you are fat-adapted, it is a glorious state of being – a sense of freedom from hunger. The key is to be well fat-adapted going into the hike, in order to most efficiently tap into one’s fat stores as one’s source of energy.
