Calorie Consumption

[Bob Gross]

Is there an easy way to estimate calorie consumption for a trip? For example, if I know my body weight, pack weight, how many miles per day of trail I expect to go, the amount of elevation gain, and maybe the average elevation and air temperature… what else is there that I need to know?

I've seen tables that estimate the number of calories to be burned per hour of running, or per hour of walking, but most of these tables don't figure the work of carrying a backpack of a given weight.

On my last trip of five days, I lost twelve pounds of body weight. A lot of that must have been simple water loss. However, it would be good to be able to estimate calories more closely.

–B.G.–

[Greg Mihalik]

Bob,
I am away from my home computer so have no references at hand, but..

Google 'metabolic equivalents'.
Look for military examples.
Apply METS to the activities and time.

Adjust for age and weight.

OR…

Take 3500 to 4000 calories per day, eat it all, weight in, adjust as needed.

[Anonymous]

Bob,

Try this link to give you a reasonable approximation. I just ran the numbers for myself and it tracks closely with what I have based my carried food on for the last few years.

http://www.backpacker.com/trail_chef_calorie_counter_calculator/blogs/daily_dirt/1818

[Anonymous]

Bob,

Here is a link to a calculator that should give you an approximate answer. Enter walking as the general category and climbing hills with a pack weighing "xx" pounds,
along with your physical data(height, weight, age, and activity duration.

http://www.shapesense.com/fitness-exercise/calculators/activity-based-calorie-burn-calculator.aspx#

[Bob Gross]

Tom, I saw that calculator, but I have a hard time accepting parts of it. According to it, an extremely active long strenuous day with a heavy pack burns only slightly more calories than 60 to 120 minutes of hiking, climbing, or skiing that involves hills and carrying a pack.

Somehow that does not compute.

For one thing, they don't define a heavy pack. Is that a certain percentage of your body weight, or is it a fixed number of pounds?

–B.G.–

[Anonymous]

"For one thing, they don't define a heavy pack. Is that a certain percentage of your body weight, or is it a fixed number of pounds"

The "shapesense.com" link in my second post gives you a range of pack weights to specify, e.g. 10-20#, 21-40#, etc, along with a range of time periods. I found it to be fairly close to my actual experience. However, for a rough cut, Greg M's suggestion would probably get you fairly close to the same result, IME. Anothe route would be to PM Richard Nisley. He has a lot of very useful information on calorie burn rates for backpacking that I found useful when I was doing my initial calculations. I only ran the numbers with a calculator after the fact to see how close the results would be, and they turned out to be in the ballpark.

[Bob Gross]

Yes, the Shapesense calculator seems to take a step in the right direction. Maybe I expected too much.

"Uphill" doesn't seem to quantify my hills, and a pack weight range of 21 to 40 pounds is quite a broad range, at least by our light standards.

Three weeks ago, I did a backpack day from 5000 feet elevation to 10,000 feet elevation over 14.5 miles, and that took me nine hours in all, counting snack breaks and stream crossings. Most of these calculators suggest that I burned around 4200 to 4500 calories. For intake, I probably consumed no more than 2500 calories that day. That explains weight loss.

I know how many METS I am capable of, at least on a treadmill.

–B.G.–

[Kevin Burton]

There are two schools of though here. At least in my head:

1. Figure out how many calories you will burn per day, pack that many calories.

2. Figure out how many meals and how often you want to eat, pack that food.

#1 means carrying more weight but maintaining your fitness level.

#2 means burning fat, and probably (certainly) burning muscle. Which means you will get weaker.

Backpacking is NOT a high VO2max sport so you aren't going to need a ton of carbs. You can burn it off your body fat.

Honestly. I'm in he #2 school right now. I just pack 3 meals a day and some snacks. Food that will keep me SANE!

This way my pack weight is much lower, and I lose weight (yay!) … the downside is I do lose muscle but I try to stay in the gym to get it back.

The only way #2 won't work is with insane thru hiking. Eventually you will get VERY tired and start starving. I don't know what strategies they are using.

[Bob Gross]

"You can burn it off your body fat."

All of the fires in Hades wouldn't be enough to burn off all of my body fat.

–B.G.–

[Andy Ledbetter]

I would use the following calculation…..

calories burned = kilometers x kilograms x 1.036

Weight in kilograms is your combined body weight and pack weight.

Most of my trips begin and end at the same so point height gained is balanced by height lost. Liner trips would need to factor in height gain/loss.
Walking speed is a very small factor that can safely be ignored.

Andy L

[Hiking Malto]

I have watched weigh gain and lose during the times that I have been training for various events. It is often very hard to tell on short duration trips what is weight lose very temporary water lose etc. But my PCT weight was long enough to remove the noise and especially the last 1500 when I only took a single zero day in that time. I had lost 12 lbs during the previous 1100 miles and frankly I didn't have a lot more to lose. So I bumped up my calories and only lost a lb during those 1500 miles. I also had planned 90+ % mail drops and being the engineer that I am knew down to calorie what was in each box. I also had a real good idea the extra calories that I added in at various town stops along the way. Bottom line is that I use 200 calories per mile with normal PCT style elevation gain, say 6k over 30 miles. This assumes a total weight out of about 200 lbs.

I rarely attempt to take the full 200 calories per hour with me unless I am doing a long training hike specifically testing my ability to eat that much. (yes, I had to train myself to eat.). Rather, I take 100 calories per mile of primarily carbs eating 300 calories an hour (3mph average) and an additional dinner that is more balanced with protein at the days end.

So, I think a calorie per lb per mile is not a bad estimate, at least for high mile days (30+)

[Mike M]

I played around the linked calculator, based on my experience I'd say it's in the ballpark- there are so many variables (individual metabolism being one) to consider that ballpark is probably as good as you're going to get (barring experience garnered from very long hikes like Greg's PCT)

on long runs (or hikes) I try to shoot for ~ 300 calories/hour; there still is an overall deficit, but performance is right up there

I usually end those episodes w/ a 3-4,000 calorie blowout, so it probably shakes out in the end :)

[Greg F]

My though is just to use your base rate per day plus x per mile. Backpacking should fall somewhere between running and walking or calories burned per hour

http://www.runnersworld.com/article/0,7120,s6-242-304-311-8402-0,00.html

So based on their formula your net burn for running is miles x .63 x weight and for walking .3 x milrs x weight (lbs)

Being 6-2 215 my bmr is 2125 plus i burn between 70 and 140 calories per mile based on the above numbers. So for a 16 mile day I would burn an additional 1000 to 2000 calories my thought and based on some weight loss measurements on 7 day trips I figure its pretty close to the middle so another 1500 calories for a total of about 3600.

[Anonymous]

"Most of these calculators suggest that I burned around 4200 to 4500 calories. For intake, I probably consumed no more than 2500 calories that day. That explains weight loss."

Neither calculators nor charts will do more than give you a place to start. Ultimately it will boil down to a process of trial and error from there until you dial it in completely based on your particular metabolism, weight carried, and terrain you hike on. It took me about 2 years to get it to the point where I felt I had it pretty well figured out. As always, YMMV.

[Anonymous]

"All of the fires in Hades wouldn't be enough to burn off all of my body fat."

Never underestimate The Devil. ;0)

[Kevin Burton]

I didn't mean it that way but I can see why there is confusion.

If you're in a low cardio volume, you body prefers to use adipose tissue/fat as its fuel supply.

So if you're in calorie deficit you will lose weight.

And yeah, eventually you will become stick and bones if you do this long enough. It isn't super healthy though as you also lose muscle.

[Robert Blean]

This thread is timely for me — it is something I have been looking into the last few days. I found some of the information on the Hammer Nutrition web site helpful — not their products, but the background nutritional information. If you have not read their documents, I recommend doing so — especially with regards too the comments about inevitably losing muscle.

I tried to use the menu planner in the spreadsheet I downloaded from BPL and found it very hard to come up with something at all consistent with my habits while also providing enough calories with a sane weight. I'm still working on that. My problem is:
*) Allow for generally acknowledged protein requirements
*) My hiking is quite aerobic much of the time, so allow for enough carbohydrate
*) Remaining food is fat, to keep the total weight down
*) So far I have been unable to do that and also fit into desired calorie/weight parameters. Still working on the problem.
*) It is complicated by the fact that I have discovered that the actual food weight (not counting packaging) seems to be about 10% more that fat+protein+carbohydrate weight.

Some reactions to a few of the earlier comments in this thread:

> #2 means burning fat, and probably (certainly) burning muscle. Which means you will get weaker.

The Hammer information explains this — after the first 90-120 minutes your body wants to get about 10%-15% of its calories from protein. Either you supply that protein or else the body will catabolize your own muscle to get it. That's what's behind their "Perpetuem" product — supplies both carbohydrates and a little protein. I'm not asserting we all need to dine on Perpetuem, but it might pay to take that information into account when planning what we do eat.

> Backpacking is NOT a high VO2max sport so you aren't going to need a ton of carbs. You can burn it off your body fat.

I'm not sure what "a ton" is, but you do need a certain amount of carbohydrate for the body to burn that fat.

I beg to disagree with the idea that day hiking and backpacking are not high VO2max sports — they certainly can can be highly aerobic. Flat country may not be so (at least for most of us), but going up hills of much length and steepness is likely to be so. Most of my hiking is up-and-down, not along ridges or river valleys, so I have come to believe I am best off treating it as an endurance aerobic sport.

> This way my pack weight is much lower, and I lose weight (yay!) … the downside is I do lose muscle but I try to stay in the gym to get it back.

Losing muscle — see above.

> Bottom line is that I use 200 calories per mile with normal PCT style elevation gain, say 6k over 30 miles. This assumes a total weight out of about 200 lbs. … I rarely attempt to take the full 200 calories per hour with me unless I am doing a long training hike specifically testing my ability to eat that much. (yes, I had to train myself to eat.). Rather, I take 100 calories per mile of primarily carbs eating 300 calories an hour (3mph average) and an additional dinner that is more balanced with protein at the days end.

Interesting figures. You are right at the upper end of what Hammer explains. They say that the most a body can assimilate is about 240-280 calories per hour, but they are talking about a 160# man and your weight is significantly more than that. What sort of calories & weight are you carrying?

> If you're in a low cardio volume, you body prefers to use adipose tissue/fat as its fuel supply. … It isn't super healthy though as you also lose muscle.

Losing muscle — see above

[Andrew McAlister]

Bob,

A very rough rule of thumb is that you burn about 100 calories per mile walked on flat level ground – speed doesn't make much difference, it is total distance covered that matters. When you start talking hiking wih a pack, on an uneven trail surface, 150 calories per mile is a reasonable planning figure. Every 660 vertical feet climbed is equivalent to walking another mile.

You then need to add in your metabolism to come up with overall calories required – this depends on height, weight and age. Google 'BMR calculator' to come up with a number specific to you.

However, the standard convention for calculating calories is to include your underlying metabolism as well. This is no big deal for running for 30 minutes, but if you are hiking all day, this can lead to a substantial overcount, so don't include the hours on the trail in your BMR calculations.

Andrew

[Elliott Wolin]

"All of the fires in Hades wouldn't be enough to burn off all of my body fat."

"Never underestimate The Devil. ;0)"

I could really use a reference to that Devil…

[Mobile Calculator]

…

[Diane “Piper” Soini]

I think most people don't worry too much about the calories of the food and instead go by weight. Anywhere from 1 to 2lbs food per day should suffice. Usually you carry a variety so the pounds of food will be roughly equal in calories no matter what you put in there. Within reason, of course.

When I hiked the PCT my strategy was to eat as much as I possibly could and then eat even more when I got to town. I never weighed the food I brought with me, and I rarely ate all of it even though I was hungry. I guess I probably ate about 1.5 pounds per day, sometimes less.

Now that I'm just an ordinary hiker, I take about a pound a day. I try to go for very nutritionally dense foods that might be slightly heavier: lots of fat, dates, cheeses, dehydrated sweet potatoes, dehydrated meats. No pasta, oatmeal, sugar or refined packaged foods.

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