personal numbers

Early August marks the State Fair in Great Falls, Montana.  The latest farm implements, horse racing, a lame midway, deep fried everything, homemade lemonade, 4H and, of course, cow chip tossing.

 

As a high school student I remember watching a rather large and enthusiastic teenager, perhaps inspired by the Summer Olympics, decided emulating a discus thrower made sense.  Perhaps so, but his release was a bit late.  It made a lovely arc and, to the delight of everyone under about twenty and away from ground zero,  an unlucky spectator served to spare the ground the full force of its impact.

 

Apart from having a good throwing arm and a bit of style the trick to doing well in the event is to select one with the right moisture content.  Too dry and they break too easily - too wet and - well - they're disgusting.  The year before watching the discus thrower I was curious about a chip's energy density - after all - early prairie settlers supposedly burned them as fuel as the prairie is mostly treeless - and found dried dung provided about 15 megajoules per kilogram - about a third the energy density of gasoline and about 20 times that of a modern lithium-ion battery.¹

 

Food is not completely metabolized .  You can completely combust food in a bomb calorimeter and learn its energy density to good accuracy, but human metabolism is very complex.  It surprises people to learn the basic rules are still based on the work of Wilbur Atwater over a century ago measuring, as carefully as he could, energy going in and that which came out unused.  But life is more complicated.   Consider the a medium potato that weighs about seven ounces - or 200 grams.  Adding up the components.

168g water    0 calories

36g carbohydrates (4cal/g) = 144 cal

4.5g protein (4cal/g) = 18 cal

2.4g fiber (2 cal/g) = 5 cal

0.2 g fat (9 cal/g) = 2 cal

for a total of about 169 calories

But that's a raw potato.  If you cook it some of the work of digestion is already done for you.  Normal cooking to a soft texture add about 38 calories taking it to 207 calories.  But your body still needs about 6 to 10 calories to digest it and you need to feed the bacteria in your gut for 2 to 5 more calories leaving you with something just under 200 calories.  Getting numbers to better than ten percent accuracy is difficult and will change person to person.  Sorting out how much energy we need as a basic couch potato is possible but not easy.  Finding the energy expended by any kind of exercise requires specialized laboratory equipment and can be very specific to an individual.  Calorie counting seems like a hopeless exercise.³

 

The bottom line is many aspects of our biology and physiology are not well known and are difficult to measure.  For a variety of reasons there is a lot of confusion about something as "simple" as what kind of a diet should we eat for the best shot at a long disease-free life.   Even measuring activity levels accurately isn't easy, but can be useful.  While they are usually dramatically off in accurately measuring the amount of work you've done, they can give a number that can be used to develop activity goals - generally not a bad thing.   People have been doing this sort of goal setting for a long time and there is evidence the current wearables are being used by the same people - not a large segment of the population.

 

But there are many measurables that relate to health that can be measured and the costs are dropping quickly.  Companies like Zephyr have wearables that can store or transmit fairly rich physiological information - information that can be very useful if it can be understood in the context of your own body and what you are doing.⁴  Motion capture combined with wearable accelerometers is making a big impact in athletics and physical therapy - it isn't a big leap to imagine it going into amateur sports and the homes of the elderly and disabled. 

 

The major issues are those of understanding the information flow - sensor accuracy, calibration, data analysis - and what it means for each person.  Some types of measurements will be more meaningful and easier than others.  Importantly who gets to use the information and for what purpose - your doctor, your insurance company, your employer, Google...? Are you processing the information locally or trusting someone else?  How secure is it?  What does HIPPA compliance mean? Are there liability issues for problems caused by low sub-par information creation? (some sensor attachments are prescription-only).  And for locally consumed information what is the user interface and experience?  Is this BJ Fogg territory or ...?

 

Just beyond our bodies is the local environment.  How good is the air you're breathing and the water you're drinking?  You probably have a smoke detector and a carbon monoxide alarm, but what about the airborne chemical soup in your home and office?⁵  In the next five to ten years we're going to be able to measure these in our homes, schools and offices with our phones and aggregate the measurements on the Net.  There are serious issues about accuracy and analysis, but it strikes me this could be an enormous driver for environmental quality.

 

There are an interesting class of environmental impacts on our physiology, health and mental state that aren't easy to quantify - beyond the easily quantified self.  The right music at the right time, high quality paper and the right pencil have an impact on thinking about a math or physics problem for me.  Closer to physiology is the intersection of my schedule and the fact that short wavelength light increases melatonin production.  The last thing I need just before going to bed is extra melatonin, so I use f.lux on my MacBook to drop the screen's color temperature starting about two hours before my normal bedtime. This is done without my interaction and I've noticed I'm getting an extra hour of solid sleep - for me that is a big deal and has increased my quality of life.

 

A decade from now it will probably seem quaint that people once thought of mobile devices as limiting as what a smartphone currently is...  of course the form factor may not be that of a smartphone.  Perhaps distributed sensors with something like a phone acting as a concentrating hub.  

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¹ If someone tells you the energy density of modern batteries is crap, ask them if it is just wishful thinking on their part.

I couldn't find a photo of the event, but did find a video of a Montanan doing it just for sport.

² The cooking, digestion and gut metabolism numbers can vary widely.

³ While it is nearly impossible to use calorie counting to accurately determine your energy balance, it can be useful if you are estimating relative calorie consumption and exercise levels 

⁴ This is being used in professional, Olympic and some Division I level sports, medical monitoring and the military.  The most difficult piece in interpretation.

5 At Bell Labs I measured the carbon dioxide level in my office at about 900ppm.  While CO₂ is not toxic in low concentrations, too much can be dangerous and it has been shown that concentrations greater than about 700ppm interfere with creativity.  I had the HVAC people readjust the airflow to keep the room under 500ppm.  A very creative company I've worked with has a strict 500ppm limit on carbon dioxide in their building and stays away from treated floors and carpeting.

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Recipe corner

 

This was for vegan friend who also worries about gluten ..  it was pretty good.  For bonus points you could throw some walnuts or pecans on top.  It would be healthier without the frosting, but carrot cake needs frosting.

 

Mostly Raw Carrot Cake

 

Ingredients

 

° 2-1/2 cups shredded carrots

° 1 cup pitte dates

° 1 cup walnuts

° 1/2 cup shredded coconut

° 1/2 tsp nutmeg

° 1 tsp cinnamon

° pinch salt

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frosting

 

° 1 cup cashews soaked overnight and drained

° juice of 1/2 lemon

° 3 tbl maple syrup (or simple sugar, agave ...)

° 1 tsp vanilla extract

° pinch salt

° 1/3 cup coconut oil (melted)

 

Technique

 

°  Blend walnuts and dates in a food processor and then everything else blending until it is an even consistency

° press into an 8x8 pan lined with parchment paper (the goo is sticky!)

° pop it into the fridge for an hour or more

° Blend the frosting ingredients into a blender 'til smooth, pour over the cake and freeze for a few hours.

° Let the cake thaw for ten minutes and slice with a knife warmed in hot water