[pct-l] Caloriic Burn Rate by Body Weight and Activity

[chelin at teleport.com (Sharon & Chuck Chelin)]

Good evening, Bruce,

Food planning is always a popular discussion and a source of concern and
endless questions among hikers, particularly those new to the long distance
hiking affliction. The questions usually boil down to, "How much?" and
 What?"  Ask a serious hiker and you are likely to get the same answer to
either question: "Everything in site, plus one pizza!"  That answer, while
usually correct, is not something you can use to plan for enjoyable,
long-term results.

CALORIES
Food is energy, and the unit most often used to measure that energy is the
calorie.  As defined in your old physics book, a calorie is the amount of
energy necessary to heat one gram of water one degree centigrade.  This is
called a "calorie", a "small calorie", or a "gram-calorie", and it is
abbreviated, "cal." with a lower-case c.  Since one gram of water is about
one-fifth of a teaspoon, a calorie is hardly a workable unit, so for food
energy measurement we use the amount of energy necessary to heat one
kilogram of water one degree centigrade.  This is a thousand times larger
than a small calorie, and is called a "Calorie", a "large calorie", a
"kilogram-calorie", or a "kilocalorie".  It is abbreviated, "Cal."  Notice
it uses the upper case C.  There is not much discipline in the food industry
in this regard, as almost everyone uses the lower case "calorie", but the
popular PC programs for unit conversion, Convert 4.10 for example, show both
"calorie" and "kilocalorie", but without explanation of the difference.

Be careful with this information.  If one of your chubby friends was to hear
that physics suggests that an average person can loose weight on 1,500,000
calories per day (1,500 Calories) they may get the wrong message and eat
enough to swell up like a tick.

CALORIE REQUIREMENTS
As advertisements usually say, "Your results may vary", but I believe I burn
around 1,800 Calories per day doing nothing but day-to-day, around-the-house
activities.  This does not include any extra exercise or work.  1,800
Calories is more than what is necessary for basal metabolism, meaning the
bare-minimum energy necessary to just keep the motor idling.  Basal
metabolism is more like spending all day on the couch watching TV; only
basal metabolism is more mentally challenging than most TV programs.  You
can pick your own number, but 1,800 Calories is a starting point that works
for me.

Actually going somewhere during the day requires more Calories.  The
"Calories per hour" measurement has the unknown of, "How fast do you walk?"
I have come to prefer the "Calories per mile" approach.  It has the unknown
of, "How difficult is the trail?"  but I find that trail conditions are more
easily predicted than my travel speed. Besides, I can more easily relate to
miles-to-go when I pack food rather than hours-to-go.

For me, at 160 lbs. and about 15% body fat, walking or running on level
ground seems to require approximately 90 Cal. per mile in addition to the
basic 1,800 Cal.  Hiking in the mountains with a pack requires more still; I
believe I will average approximately 110 Cal. per mile rather than the 90
Cal.  Therefore, if I hike 10 miles per day, I plan for 1,800 + 1,100 =
2,900 total Cal.  If I hike 30 miles per day I plan for 1,800 + 3,300 =
5,100 total Cal. etc.  The caloric demand of hiking longer periods, for
example more than 60 days, is usually greater so I plan on 125 Cal. per mile
after that period.

There can be great differences in energy demand depending upon your size,
age, your individual metabolism, and the trail environment.  We all know of
people who eat like a bird and still book the miles.  We also know others
who eat like a plague of locusts, and always seem to be hungry.  It is
probably not a coincidence that most of the locusts are teenage guys who
have the metabolism of a red-hot coal stove.  When those guys go into the
mountains the bears hide their own food in trees.  Trail environment also
changes the Calorie demand.  Summer temperatures in moderately graded Oregon
have one fuel demand, while the steep N. Cascades in cold, wet weather has a
higher fuel requirement.  Once again, pick your own number, but 110/125 Cal.
per mile is a good starting point and has worked for me in the N. Cascades.

Eat up...

Steel-Eye

----- Original Message ----- 
From: "Bruce Harvey" <bharve@dslextreme.com>
To: "Mark Verber" <verber@gmail.com>
Cc: <pct-l@mailman.backcountry.net>
Sent: Sunday, October 31, 2004 6:04 PM
Subject: Re: [pct-l] caloriic burn rate by body weight and activity


> Mark,
>
> Thanks for your post, on the topic of 'The Diabetic Backpacker', with a
link
> to your website.  I'd forgotten, you've gathered some really useful links
> there!  http://www.fitresource.com/Fitness/CalBurn.htm  Has
calories/hr/Lbs.
> body weight for 'hiking- cross country'.  I'm curious whether you've
> established  a personal range of calories/hr. at your body weight for a
> range of miles/hr.    Anyone else?
> Regards
>
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