I need a bigger bear canister

My shakedown hike on the John Muir Trail highlighted several gear issues, but in this post I’m going to focus on the bear canister. In particular, the calorie restrictions it imposes. I started my hike by accessing the PCT via New Army Pass. I then headed for Mount Whitney and the start of the JMT. This was my resupply schedule:

  • Horseshoe Meadow to Onion Valley: 5 days
  • Onion Valley to Muir Trail Ranch: 5 days
  • Muir Trail Ranch to Red’s Meadow: 3 days
  • Red’s Meadow to Happy Isles: 5 days

The first day’s food after each resupply didn’t need to fit in the bear canister, assuming I could eat it all before bedtime. So at most, the canister had to contain just over four days’ worth. The canister I used was the Backpacker’s Cache (a.k.a. the “Garcia”) because I’ve had it for several years, it’s on the “approved” list, and it’s never caused me any problems.

OK, that last point isn’t entirely true. The first time I used the Garcia was in Denali National Park. I didn’t do a particularly good job of packing it, so on the fourth (final) day, I ran out of food. Fortunately, I encountered plenty of blueberry bushes and several obliging tourists so I was able to scavenge some extra calories. I’ve since learned that heat, exertion and altitude all tend to suppress my appetite, and this has allowed me to carry less food. However, before the JMT, I hadn’t hiked far enough to notice the weight-loss that accompanies insufficient calories. Most of my prior food-related problems had instead been caused by eating too much before attempting a steep climb.

Before mailing my JMT resupply packages, I ensured that each one would fit in the bear canister. I have the vague recollection that each day’s total was about 3000 calories. In hindsight this wouldn’t be enough, but at the time it didn’t occur to me. Based on previous hikes, it looked to be about the right volume of food. Occasionally, hikers I met on the JMT had spare food and I gratefully accepted any that was offered.* I also consumed more than my fair share of the contents of the hiker buckets at Muir Trail Ranch. In spite of this, I was aware that most days I needed to tighten my hip-belt just a little. After returning from the JMT, I knew I should take my energy requirements a little more seriously on the PCT.

Basic energy requirements

  • Body-weight = 172 lbs
  • Approximate body-fat ratio = 10 %
  • Lean muscle = 172 x 0.9 = 155 lbs
  • Assumption: each pound of muscle burns 10 calories per day
  • Resting metabolic rate = 155 x 10 = 1550 cals/day

Hiking energy requirements

  • Total distance = 252 miles
  • Total duration = 18 days
  • Average speed = 252 / 18 = 14 miles/day
  • Assumption: walking a mile burns 100 calories
  • Hiking expenditure = 14 x 100 = 1400 cals/day

So my minimum daily on-trail calorie requirement should be about 2950. The true number will be higher (much higher, it turns out) due to increased metabolism, elevation changes, the weight of my backpack, etc. If I take into account the weight I lost during the hike, I can estimate my actual calorie needs.

Total energy requirements

  • Weight loss = 9 lbs
  • Rate of weight loss = 9 / 18 = 0.5 lbs/day
  • Assumption: a pound of fat contains 3500 calories
  • Calorie deficit = 0.5 x 3500 = 1750 cals/day
  • Total calorie burn rate = 2950 + 1750 = 4700 cals/day

Obviously this is just an estimate, but it’s still a surprisingly large number. It tells me that I need to eat more on long distances, even if I’m not aware of it. On the JMT, I remember getting quite hungry mid-morning each day, but a small snack was enough to stop my stomach rumbling. I also had a craving for fruit (and beer) by the time I reached Red’s Meadow. Neither of these sound like the typical definition of “hiker hunger” though, so I guess I’ll have to rely on the numbers.

Which bear canister to buy?

I’m thinking one of the larger Bearikade canisters – either a “Blazer” or an “Expedition”.

*I’d particularly like to thank the group of retirees that Edwin (a.k.a. “Boomerang”) and I met at Sallie Keyes Lakes. They’d spent the day fishing, and had enough left over to be able to offer us several freshly-grilled trout. By far the best meal I had during the hike.

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