Like many, I was taught to bring plenty of carbs backpacking. But I've been low-carb in real life for a couple years and thought to try it on a three-night trip I took last weekend in the Strawberry Mountain Wilderness (Malheur National Forest, Oregon, USA). I brought fat and protein in the form of tinned anchovies and sardines (packed in olive oil), pouches of tuna (also in olive oil), summer sausage, beef sticks from U.S. Wellness, a little bottle of coconut oil to sip on while hiking, and so on. The only carbs were a smattering of dried blueberries added to a bag of walnut halves for a bit of trail munching.

Rather than make meals, I snacked as needed.

The gross weight of my food bag was 5-3/4 lbs (2.6 kg) when full, and 1-1/4 lbs (0.6 kg) when I returned. These weights include the bag and food packagings, so the figures are rough, but it looks like I ate about 1-1/2 lbs (0.7 kg) of food a day. I'll use this number for planning the food for my next trip.

Interestingly, I didn't develop cravings for junk food, like pizza, which I always used to do when eating the traditional carb-rich backpacking diet; I was never really hungry, I never "bonked," and I felt good with plenty of energy.

Same here! It occurred to me that if you want to improve fitness and burn fat then it's no help to be constantly chomping down sugars and carbs. I had already found off the trail that no breakfast at all is better than a high carb breakfast. So I've been moving towards the same kind of food for hiking that I eat normally and it works fine. Occasionally I fall behind because everyone else is constantly drinking energy drinks and snacks but there is no need for that stuff unless you're some kind of competitive athlete.

How many miles?

Today with no food and didn't bonk. Without a measure of intensity the response to the post could be a yawn all the way to wow. If you did 12 miles over twelve hours then sure you could probably eat anything or frankly nothing at all. You could keep up with calorie expenditure with fat burning. Now do the same diet and hike 30 over 10 hours without bonking and it would be somewhat surprising and impressed. Remember, marathon runners don't normally bonk until about mile 18. Hiking would likely be further since it lower intensity in most cases.

Edited by gg-man on 07/23/2012 19:14:09 MDT.

David asks, "How many miles?"

The longest day was 8 miles with an elevation gain of 1,900 feet over a pass at 8,350 feet. That's not impressive by the standards of many, but I'm 62, with a fused ankle and titanium knee. I know that without nutrition, I would have bonked that day because a few weeks earlier I went up and down 1,400 feet on a 4-mile hike and totally bonked about 300 meters from camp. I barely made it back.

So sipping on a little coconut oil, chewing on a few beef sticks, and some walnuts, I came nowhere close to bonking on the latest trip.The entire trip was 22 miles and I felt fine. Apparently one does not need to pound down handfuls of M&Ms to keep the old muscles fueled.

This is what my nutritionist told me a couple years ago, and I was skeptical. I stand corrected. At least for the amount of energy I put out.

Back in 2007 I walked the Tour de Mont Blanc. I had never done a trip over 5 days long and I wasn't quite sure how to prepare for this. I brought lots of sweets and quick cook food with lots of carbs and thought I was all set. On my second day out, in the evening, after a long hard day climbing, suddenly I started going into serious hypoglycemia (I'm diabetic), and my sweets couldn't keep up. I ran out of carbs to eat, hunkered down at the side of the trail, and probably would have died on that mountainside if another hiker, a sweet elderly woman who was carrying a bag full of candies, hadn't come along and helped me the last few hundred meters to the refugio. The next day, down in a nearby town, I bought a big salami with a hunk of cheese and a big loaf of local farmer's bread. I ate the bread sparingly, but chowed down for lunch on a lot of sausage and cheese. I walked all day and never once felt my blood sugar go down. For the rest of the 9-day trip this is how I ate as I walked during the day. I never needed to eat any sweets of any kind again.

I was wondering only because at a certain intensity level defined by pace times distance, one's body will burn whatever fuel you put into it be it carbs, fats or proteins at a very high rate. The metabolic rate at that point only want calories. And lots of them.

I find that 'bonking' is the result of not monitoring a constant feed of calories during high exertion, rather than what you may specifically be putting into your body. Smaller meals throughout the day keep my glycogen stable. If I keep the calories coming, I don't bonk. This has been my experience anyway.

Notably, what you are eating is high in calories.

"I would have bonked that day because a few weeks earlier I went up and down 1,400 feet on a 4-mile hike and totally bonked about 300 meters from camp. I barely made it back. "

I suspect that what you call bonking is a bit different than the normal definition. It would be highly unusual to bonk after only 4 miles even if you ran it, unless you went into it with glycogen levels extremely low, which would be unusual. See http://en.wikipedia.org/wiki/Hitting_the_wall

I tend to agree with Greg, but from the perspective of being a non-diabetic. I can hike all day without ANY food and have no problems. I can do this day after day as long as I replace my calories in the evening. So, unless you are shooting insulin and absolutely need some carbs to balance the insulin, there is no reason a 'normal' person should bonk, unless you are moving a lot of distance at an Olympic/Tour de France pace. Many marathoners 'bonk' due to having their bodies accustomed to running on carbs rather than fat. If they took more care to acclimatise to burning fat as their primary fuel, they possibly wouldn't have such problems, but quite literally YMMV. Since fat weighs less than carbs or protein, it makes a lot of sense to me that a true UL hiker would carry and eat mostly fat, but I wonder if you really need a slow trickle of constant fat to sustain the effort. Unless, of course, you are so lean that you have very little fat reserves, then you might need a more constant supply.

Greg wrote, "I suspect that what you call bonking is a bit different than the normal definition."

You could be right. But I don't know what to call it. Here's what happened: I hiked to the top of the peak, drank some nice hot tea, took in the view, explored the various radio transmitter structures, then turned around and walked back down the way I came.

So thar I was: chugging along nicely on a mostly level trail, nearing camp, all full of pep and vim and admiring the scenery when about 300 yards from camp I felt my legs--quads, I think--suddenly lose power. Like someone pulled the plug.

I slowed. Moments later my entire body ran out of fuel. I'd manage ten or so paces and have to stop and lean on my trekking poles to recover for the next ten paces. I felt completely exhausted. It did not feel like low blood sugar, but like my batteries had been yanked. Managed to drag my sorry a$$ back to camp and collapsed into a chair.

My first thought was that I needed to boost my blood glucose with dietary sugar, but I resisted and instead ate a packet of tuna in olive oil, with, of course, a little Srirachca Rooster Sauce on it (I'm not an animal!). Within ten minutes I was almost completely recovered.

Any guesses on what happened?

[Edit: having had that experience, I decided that on this trip I'd nibble on protein and oil while hiking, and though the distance and elevation gain on this trip's hikes were greater than the hike I described above, I did not experience that sudden deflation of energy.]

Edited by JackElliott on 07/24/2012 09:36:20 MDT.

Hi Jack,

I had that very same feeling of heavy legs and out of gas feeling.

It was hot and humid but nothing outrageous. I had covered this section of trail in much these same conditions before without a problem.

I was drinking plenty of water and I had plenty of hard candy and granola bars to nibble on while I was hiking.

What others on this forum suggested to me and has seemed to help was to somehow introduce potassium into the mix. I did that by the inclusion of Gatorade and Clif bars. I nibble on the Clif bar as I walk. It usually takes me about an hour or so to go through one Clif bar taking a bite every now and then.

Gatorade is a good source of electrolytes and you can carry the powder in your pack so that you can mix it weak or strong as per your taste.

Party On,

Newton

Exact same thing happened to me once. Like lead in my limbs so I couldn't move them.

Walked down 7 miles and 3500 feet elevation loss without eating or drinking, because it was raining and I didn't feel like stopping.

Then I ate and drank and rested for 30 minutes and I was back to normal.

I don't know if it was water or food or both (or something else).

Interesting, but I don't think my issue was one of dehydration or electrolytes loss. The weather was cool, I didn't work up a sweat hiking to the top of the peak, drank plenty of fluids (couple pints of hot tea at the top), and my morning's breakfast, consumed but an hour before embarking on my little trek, had plenty of minerals, vegetables, and other electrolyte-bearing stuff in it.

It was a very weird experience. Like operating on a nearly-dead battery.

Tea? I wonder if you became overheated and your body stopped sweating. We're you dizzy?

Not even close to overheating. It was a cool day, I was lightly dressed, I drank the tea at the peak of the mountain where it was pretty darn cool because of the wind (glad I brought a windbreaker), the hike back down was downhill almost all the way, and it was an hour after the tea that I experienced the abrupt loss of energy. I grew up hiking in SoCal where desert heat is a constant companion so I know from overheating.

It sounds like it could be something to do with your. Blood pressure falling. Have you experienced this again and /or have you seen a doctor?

As an old guy I see my doctor three-four times a year. Low BP has not been diagnosed, in fact I take a mild ACE inhibitor (Lisinopril) nightly for hypertension. I did not experience dizziness when the my body's battery drained, just massive exhaustion. Step, step, step, pause, step, step, step, pause--wash, rinse, and repeat.

I was pretty sure my body just ran out of glycogen, but now I'm wondering if it wasn't something else.

Who knows when you might be able to reproduce/experience this event again...

Throw a couple of honey packets (or similar and more durable) into your kit and leave them there.
If this ever happens again, suck 'em down and observe the results.

It's my opinion that my crashing was caused by lack of glycogen, but I didn't have any way of testing it. Sucking on a honey packet, or similar, would be one way to see whether my blood glucose needed boosting. As it was, a few minutes sitting and some tuna resulted in complete recovery in short order.

"instead ate a packet of tuna in olive oil, with, of course, a little Srirachca Rooster Sauce on it (I'm not an animal!). Within ten minutes I was almost completely recovered."

Likely something else. I don't know what the sugar content of the Srirachca sauce you used was, but tuna and oil would both take a while to digest to have any impact on your blood sugar...certainly a lot longer than 10 minutes. It sounds like your leg muscles ran out of glycogen, for whatever reason. You may have found just sitting and eating nothing at all would have had the same effect, as it would give your muscles some time to replenish glycogen from blood glucose.

OTOH, you may have reactive hypoglycemia due to impaired glucose sensitivity (thus raised insulin levels). This condition would certainly be improved by eating a low carb diet, both on the trail and in daily life, but doesn't explain why you recovered so quickly after eating a protein and fat meal.