Friday, January 27, 2017

Walk Thoughts #1: food on the trail

I'm starting a walk-related series called "Walk Thoughts" that will be devoted to writing about all aspects of my upcoming Seoul-to-Busan walk. Today's post will be the first entry in that series; topics won't be in any particular order: this will be more of a desultory, "as I think of it" kind of ongoing meditation. By titling the series "Walk Thoughts," I'm making it easier for you to search for these posts: in the future, after I've done a few entries, just type "walk thoughts" in my blog's search window (up top), and all the posts with that title will appear. Click "arrange by date," and you can read through the posts chronologically.

So today: let's talk food.

It's pretty basic—no food, no life. A walker needs food on his walk if he hopes to live to the end of it. If I'm going to be walking around eight hours a day for twenty-one days straight, I'm going to need some level of nourishment. In my case, since I come pre-loaded with a surfeit of fat cells, I probably won't need all that much food on the trail. This is important to keep in mind; I'll be coming back to this fact soon.

As I'd mentioned earlier, I'm currently looking at three major types of nourishment: (1) MREs, (2) Soylent, and (3) Survival Tabs. I may have to add a fourth possibility: good old Mountain House food packs, which are freeze-dried, along with being arguably lighter, smaller in volume, more durable, and above all, tastier than MREs. (I reviewed plenty of Mountain House food packs here. They are indeed tasty, and I unhesitatingly recommend this brand over all others.) There are several factors to consider:

1. How heavy will a 21-day supply of food be?
2. In terms of value, what is the per-calorie cost?
3. How much actual space will a 21-day supply of food take up?
4. Do I really need a 21-day food supply, or can I get by with a 10-day supply?

The answer to question (4) is a big yes: I can get by with only ten days' worth of food. With all the aforementioned fat cells, and with an every-other-day supply of nutrition, I have zero chance of starving to death on the trail. I might lose weight, but in my current state, that's actually a desirable outcome, not something to fear.

While I plan to talk more about encumbrance in another Walk Thoughts entry, I can say now that encumbrance is a major consideration, given my knees, which haven't improved much since 2008. Here's what I can say about my knees as they are now: they get me everywhere I need to go during a normal work day, and they're fine when I do my creekside walks, whether we're talking about the truncated walks that I currently do or the much longer, five-hour walks I was doing several months ago in warmer weather. If anything, the long walks showed that my knees weren't the problem: my feet and my hip joints were what ended up achy.

But the moment you factor in the backpack, the knees become a concern again. From my 2008 walk, I remember that I was able to walk a good 20 miles a day while wearing a friend's Alice pack (a type of US Army external-frame backpack made of heavy canvas, but with a very light frame) and carrying a much-reduced load on my back—somewhere in the neighborhood of 15-25 pounds as opposed to the monstrous 60 pounds that I'd been hauling beforehand. During that less-encumbered period, there were no knee problems, no back problems, no nothing.

Upshot: in terms of encumbrance, I need to keep my backpack's weight down under 35 pounds. In the meantime, I personally need to lose at least 20 pounds of fat (not water) before I begin the hike in May. With the weight loss and the reduced backpack load, I ought to be just fine on this trek: I'll be able to maintain a pace of about 3 miles an hour, making it possible for me to hike over 20 miles a day if need be.

So how do the numbers add up if I'm working with a ten-day supply of MREs or Soylent or Survival Tabs or Mountain House? Here's the tale of the tape:

The US military's "meal ready to eat," or MRE, has become culturally iconic on the American culinary landscape. Love it or hate it, its consumption has expanded beyond the military: there are civilian versions of MREs out there (which aren't much better in quality), and plenty of people laud MREs for providing surprisingly tasty, and reliably rib-sticking, meals. The rib-sticking nature of MREs probably has something to do with those huge, dry crackers that come in every pack, and the meal's main course is also normally quite carb-heavy. MREs have a shelf life of three years if stored in ideal conditions, but once conditions become too hot or too cold, that shelf life can drop down to as short as one month, according to experienced hikers. This means that MREs are probably not the best food to keep around for survival/emergency/bug-out-bag purposes; they're also bulky compared to other food alternatives, according to some complaints.

That said, I count myself a mild fan of MREs. They'll never win any culinary awards, but the meals they provide are sufficiently filling, giving you energy to get through the day. I take to heart the warnings about their heaviness and bulkiness—both qualities being major considerations for my journey. Let's examine the weight/bulk issue in depth:

1. How heavy will a 10-day supply of food be?

The average MRE weighs 625 grams, or 1.38 pounds. That's quite a lot, but keep in mind that the main course inside an MRE already contains water; it's a lot like opening up a can of Chef Boyardee "spaghetti" and eating that: everything is pre-cooked, so the only thing you need to do is heat the food through. MREs come with a chemical-heat source (filled with reactive metals like magnesium); that also undoubtedly contributes to the heaviness.

So: 625 grams x 10 = 6,250 grams, or 13.8 pounds. If it's a ten-day supply of food, that's not horrible. I haven't had a chance to put together my gear yet (I'm ordering plenty of supplies from the States, but am also planning to shop for some supplies here in Korea), but I suspect that I can keep the weight of my non-food items below 20 pounds. So 13.8 pounds' worth of MREs is doable, at the very least.

2. In terms of value, what is the per-calorie cost?

The average MRE supplies a hiker with about 1,200-1,500 calories per pack. For a big guy like me, I can maintain weight by eating two packs a day, thus supplying me with close to 3,000 calories. I'll be eating half that amount, and only every other day, so there'll be significant weight loss along the trail, but the result will look worthwhile, I think. Right, ladies?

The cost of MREs varies with where you buy them. Perhaps the cheapest option is eBay, and one guy is selling two boxes of "Case A" and "Case B" meals—24 meals total—for $188 plus $54.71 for shipping to South Korea. Let's do the math:

24 meals x 1,350 calories (avg.) = 32,400 calories

$188 + $54.71 = $242.71 for purchase and shipping

242.71/32,400 = $0.00749 per calorie, or about $10 for a 1350-calorie meal.

It's the shipping cost that's killing me, here: if shipping were free, the cost would drop to around $8 per meal. I'll keep looking around for cheaper MRE options. Perhaps eBay isn't the cheapest venue, after all. (I see that Amazon is selling the same two boxes for $190, but shipping to Korea may possibly be free.) I remember buying MREs off the black market in Seoul for under $6 a package.

3. How much actual space will a 10-day supply of food take up?

An MRE is 3.5 by 5.5 by 8.5 inches. That's about 164 cubic inches. Ten such packs would take up 1,640 cubic inches in my Gregory backpack, which has a 95-liter storage capacity (REI no longer sells this beautiful pack, alas). 1,640 cubic inches converts to 26.9 liters, so that's around a fourth of my pack's space being taken up with food. Not horrible, but maybe we can do better as we move to examine other food alternatives.


Soylent is a scientifically engineered meal-replacement drink that comes in two primary forms: (1) a bottled, flavored, shake-like liquid and (2) a bagged, powdered, just-add-water drink. Rhett and Link, on their Good Mythical Morning show, describe Soylent as tasting like "Cheerios milk," i.e., the milk that's been interacting with a bowlful of Cheerios for a while. I have to wonder whether I can drink Cheerios milk over the course of three weeks and not go insane. That said, Soylent is apparently fairly cheap in terms of per-meal cost, and as Michael Stevens of the YouTube channel VSauce recently proved, you can drink nothing but Soylent for three days and suffer no ill effects.

Also of note: Soylent has a one-year shelf life in ideal conditions, and it requires no refrigeration—an important consideration out in the boonies.

1. How heavy will a 10-day supply of food be?

If we're talking about bottled Soylent (which many customers say is better-tasting than the dry powder), then each Soylent bottle weighs 414 grams (14-15 ounces); the plastic bottle itself has an approximate weight of 15 grams. That's 429 grams total, per bottle. If each bottle provides only 400 calories, then the caloric equivalent of an MRE is about three to four bottles. If I'm drinking three to four bottles per day, every other day, then a ten-day supply of Soylent will be 30-40 bottles—let's use an average of 35. 35 bottles x 429 grams = 15.015 kg (33.1 pounds!). Incredibly, that's heavier than ten days' worth of MREs. (You'll recall, above, that ten days' worth of MREs will weigh 13.8 pounds—less than half the weight of liquid Soylent!)

So bottled, liquid Soylent is already looking like a no-go, just from the weight perspective. What about the powdered form, then?

A pouch of dry Soylent contains 460 grams of powder. Each pouch contains four servings' worth of Soylent, and each serving, in this form, is 500 calories, not 400. I seriously doubt that I'll use 3/4 of a pouch in a single day's worth of meal-consumption: quarter-full pouches will get annoying very quickly, so I'm most likely to consume an entire pouch's worth of Soylent in a single day. That way, I can roll up the empty pouch and stow 'til I throw. I have no idea how much the pouch itself might weigh, but I think 10 grams isn't far off.

So: 460 grams of powder + 10 grams for the package = 1 day's supply. Ten days' worth of powdered Soylent would therefore weigh 4.7 kg, which is a hell of a lot lighter than liquid Soylent. Since I'll be walking alongside rivers the entire length of this half-peninsula, water won't be an issue, especially if I'm using that Grayl filtration system. So that's covered.

Powdered Soylent is already looking like a winner, here. Ten days of Soylent is 1.5 kg lighter than ten days of MREs.

2. In terms of value, what is the per-calorie cost?

Apparently, Soylent is cheapest when you buy it directly from the Soylent website and not from a retailer like Amazon. The website sells a package of 42 bags (which it claims will make 210 meals) for $324. The site says that this comes to a cost of $1.54 per 400 calories, which gives us a per-calorie cost of $0.00385. If we compare this to a 1,350-calorie MRE meal, that's like paying only $5.20 per MRE. Of course, I didn't factor international-shipping costs in; that would probably jack the per-meal price up to around $7 or even more. Still, Soylent trumps MREs in terms of cost.

3. How much actual space will a 10-day supply of food take up?

At this point, we can assume that, if I'm going with Soylent over MREs, I'm going with the powdered form, which is exponentially cheaper. I'm unable to find dimensions for individual packets of powdered Soylent, but a 21-meal box of Soylent has package dimensions of 11.8 x 6.8 x 10.1 inches, for a total of 810 cubic inches. If we chop off 15% of that volume to account for the bulky, cardboard packaging, we get about 689 cubic inches, which converts to 11.3 liters, or roughly 2.5 liters per pack (assuming 4-5 packs per 21-meal box). That's 25 liters of space taken up, which is slightly better than the 26.9 liters calculated above for MREs.

All in all, Soylent may be the more boring choice for nutrition, but it's significantly cheaper, lighter, and less bulky than MREs are.

Survival Tabs

Opinions on Survival Tabs vary across the spectrum from hiker-love to all-out hatred. They look like exactly what they're billed to be: huge tablets of nutrition. They're marketed as a meal-replacement solution for outdoor and survival situations. For what it's worth, Survival Tabs have a customer rating of 4 out of 5 over at Amazon. While it's hard to imagine a more boring food source than Soylent, Survival Tabs might actually be even more boring.

Survival Tabs have an estimated unopened shelf life of 25 years under ideal storage conditions (this goes down to 90 days after opening), but suffer little if any deterioration even in extreme heat and/or cold, or so the makers claim.

All the same, I have practical questions:

1. How heavy will a 10-day supply of food be?

A single pack of 24 tablets is supposed to last a person two days (i.e., you eat 12 tablets a day, or four per meal for three meals). 12 tablets is 240 calories, so the Survival Tabs makers aren't kidding about bare-minimum survival: if you're using these tablets, you're merely trying to stay alive and minimally nourished, which makes Survival Tabs the most austere nutritional option thus far. lists the "item weight" at 3.2 ounces. I'm unsure whether this accounts for the bag as well as the tablets, so to be safe, let's round that figure up to 4 ounces. A ten-day supply of tablets, then, would weigh 40 ounces, or an incredible 1.13 kg.

This is by far the lightest of the three options examined up to now, but it's also the one that's most likely to crush my soul. I want to bask in Korea's beauty as I walk through it, but part of that experience, for me, has to be the enjoying of a decent meal. Running on nothing but Survival Tabs for the entire length of South Korea might end up sucking all the fun out of the experience. Am I willing to risk that just to shave off a few pounds' encumbrance?

2. In terms of value, what is the per-calorie cost?

A single pack of 24 tablets costs $8.95 plus shipping, and shipping could conceivably double the purchase price, especially if Amazon refuses to ship these to Korea. Let's assume the worst and double the purchase cost, so: $17.90 for a 24-tablet pack. At 480 calories per 24-tab pack, that's a per-calorie cost of $0.037 per calorie—much more expensive than either MREs or Soylent. To make the MRE equivalent, multiply by 1350, and a Survival Tab meal costs $50.34 for an MRE-sized portion of calories. Of course, that's not how we're supposed to use Survival Tabs: we're supposed to ingest only 240 calories per day, so a day's worth of Tab-eating will come out to $8.95.

We haven't even gone through all the set questions yet, and I'm already not liking Survival Tabs as an option. They're expensive on a per-calorie basis, and they might trigger bouts of depression during a long hike that will likely include dreams of gourmet meals.

3. How much actual space will a 10-day supply of food take up?

Amazon lists the "product dimensions" for Survival Tabs as 2.8 by 5.5 by 8.5 inches. That's 130.9 cubic inches for two days' worth of food. Multiply by 5, and that's 654.5 cubic inches, or 10.73 liters. That's much, much smaller than the 25-27 liters taken up by Soylent and MREs.

Survival Tabs are also sold in huge plastic bottles that remind me of dog food. I could repackage the tablets in Ziploc bags to save space, but all in all, I'm not too motivated to buy Survival Tabs.

Mountain House freeze-dried food packs

Having already thoroughly reviewed Mountain House products elsewhere, I already know that, in terms of taste and quality, this is the food option I most prefer.

Mountain House products do present something of a challenge, though, in terms of calculating cost, dimensions, etc.: the problem is that a single package of freeze-dried food (you reconstitute it with boiling water, which means I need a heat source while hiking) is usually meant to serve 2-3 people. True: when a package says "serves 2-3 people," that's usually enough for just one Kevin, but another challenge with Mountain House is that, because the meals are varied, the serving sizes and costs will also vary. It's probably best, then, to use maybe three different meals as a representative sample, then average those meals out to get the requisite numbers for the questions that follow.

Those three meals:

Lasagna with Meat Sauce, 2.5 servings, $9, 4.8 ounces (136 g), 240 cal/svg
Beef Stroganoff with Noodles, 2.5 servings, $9, 4.8 ounces (136 g), 260 cal/svg
Grilled Chicken Breasts with Mashed Potatoes, 2 servings, $11, 3.7 ounces (105 g), 210 cal/svg

Average cost per single serving: $4.23
Average weight per pack: 4.43 ounces (125.6 g)—round to 5 ounces (+ bag)
Average calories per serving: 236.7

Final bit of trivia: Mountain House freeze-dried meals come with a thirty-year taste guarantee. In other words, if I were to buy a package of Mountain House right now, I'd likely be dead before the thing went bad on my shelf.

1. How heavy will a 10-day supply of food be?

At an average of 5 ounces per bag, that's 50 ounces (1.42 kg), only 10 ounces heavier than Survival Tabs, and a whole hell of a lot tastier.

2. In terms of value, what is the per-calorie cost?

This is where Mountain House falls down. At an average of 557 calories per bag, and an average cost of $9.67 per bag, we get a per-calorie cost of $0.017. For a 1350-calorie meal (MRE equivalent), that comes out to $23.44. Compare that to the $5.20-per-MRE value of Soylent. Ouch.

But you're paying for quality, and that might be worth it during a hellish, three-week slog.

3. How much actual space will a 10-day supply of food take up?

Amazon is listing the "item dimensions" for Mountain House Beef Stroganoff at 9.5 by 8 by 2.3 inches. That's a decent standard, and those dimensions come out to 174.8 cubic inches for one pack. Ten packs would therefore take up 1748 cubic inches, or a whopping 28.6 liters in my backpack.

Overall, Mountain House is definitely tops for quality and lightness, but it's an expensive, bulky option that will make life difficult for me when I'm packing.

Yet here's the thing: as I hike along and reach those way stations, I'll be throwing away the emptied-out packs of food, thereby increasing the free space in my backpack and lightening my load, several ounces at a time. Bulk is a relevant issue, but only at first. Over time, it becomes a non-issue. As long as I can stuff all the food packs in and keep the total weight of my backpack under 35 pounds, I really ought to be fine, no matter how bulky my food might be. My knees care only about weight.

Having looked at the options in some depth, now, I'm very tempted to go with Mountain House as my nutriment of choice. Then again, there's nothing stopping me from selecting a combination of the above foods as a way to keep weight and bulk down; that's another thing I'll be thinking about over the coming weeks and months.

Well! That's it for my first-ever Walk Thoughts. Sorry if all the math was boring (and do tell me if you think I've gotten the math wrong... I've been known to overlook certain factors and/or make goofy mistakes), but thanks for joining me in this thinking-out-loud session. Here's a quick chart summarizing my findings (winners in green):

Until next time!

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