The Fugue

I think I’ve posted on this before, but I want to post my method for weight loss again, and try to do it in as few words as possible this time. If you want more information about the principles upon which I based this method, read Total Fitness in 30 Minutes a Week by Laurence Morehouse, and The Hacker’s Diet by John Walker.

First, why you should care: I lost 40 pounds eating whatever I wanted and have kept it off even after joining Facebook and eating up to 3 meals a day at the gourmet buffet plus micro kitchens.

Second, why you may not care: you want to lose more than 2 lb / week (good luck with that) or you are a masochist.

Here’s what you need: a piece of graph paper, a pencil, and a bathroom scale (digital is best). Oh, and a little patience and a small amount of willpower (much less than your average diet requires). To set up all you need to do is draw a line in the corner that goes over 5 squares and down 1 square for a weight loss rate of 1 pound per 5 days, you can choose any weight loss or gain rate that you want as long as it’s not more than 2 pounds per week. Obviously, the faster you lose the more willpower you need, but no matter how much willpower you have it won’t work if you go much over 2 pounds per week.

Here’s what you do every day: just after you wake up you use the bathroom and then step on the scale—before eating or drinking anything. Mark your weight on the graph paper. Then, imagine the line that best fits the marks for the past 5 days (least squares fit for you mathy types).

Is that line sloping down more steeply than your reference line? Congratulations: you can eat as much of anything you want today. Don’t gorge yourself, but don’t fret it. Want that ice cream? Go for it. Candy bar? Sure. Triple burger with guacamole? Ok, but think about making it a double man.

Is that line flatter than your reference line (or going up)? Then today you still get to eat (almost) whatever you want! But, we need to restrict quantity. In specific, we need to eat about 500–800 calories less than your normal intake. You can accomplish this easily by eating smaller portions at meals and skipping dessert.

That’s it. Fast forward 1 year and if you have stuck with the plan you will have lost as much as 70 pounds. But we know life (and holidays) happens, so be realistic and figure you’ll fall off the horse a few times. No big deal, this system is designed to keep your morale up and recover gracefully. To be safe, expect 40 pounds per year, then be pleasantly surprised.

There is no correlation between what you eat today and what you weigh tomorrow. Well that’s technically a lie, but there are much bigger effects than what you ate. Your weight will fluctuate as much as 2 lb due to various effects. You have no control over this. The method is not relying on any correlation between today’s diet and tomorrow’s weight. It is relying on the long-term effects of eating smaller portions approximately half the days (maybe even less). If you weigh more today it doesn’t mean you failed yesterday! If you weigh less today it doesn’t mean you succeeded yesterday! You have to take the long-term view and just stick with the program.

Now some short notes. First, exercise is a good idea. No, a great idea. Although it’s not essential to this plan, I think you’ll find it helps you with appetite control and to just feel better all-around. Second, eating healthy doesn’t hurt either, obviously.

A couple days back I posted my idea for measuring body density and estimating
body
fat.
Dad, who has a set of skinfold calipers gave it a try and gave me comparative
results, and asked the question on everbody’s mind: just how accurate is it,
especially with that pretty blatant guess at residual lung volume?

So I took some time to learn how to account for uncertainty and take a stab at
pinning a confidence interval on the technique. First of all, I didn’t realize
how complicated uncertainty propogation is. Partial derivatives, squares and
square roots, etc. Luckily, I came across some lecture or presentation notes
detailing a sequential perturbation method (instead of an analytical method). I
could have talked Jacob into walking me through the partial derivatives, but
this method is easy to code and a find in and of itself. Read about it in this
PDF.

I coded up the formula and ran some test data through it. Here’s the equation
again for review: ρ = m / ((m + m_c)/ρ_w – (v_a +
v_c + v_r)) Here’s the values and uncertainty I attribute
to each variable:

• m = 121.29 ±0.02 kg
• ρ_w = 0.997 ±0.001 kg/l
• v_a = 1.13 ±ٍ0.01 l
• v_r = 1.87 ±0.5 l
• m_c = 0 ±0.02 kg
• v_c = 0 ±0.01 l

I didn’t actually use a counterbalance, but I included the uncertainty in
measuring its mass and volume as if I had, just for completeness. As suspected,
v_r has the largest uncertainty. I calculated the uncertainty if
v_r were magically accurate, and found that the uncertainty was
0.0014 kg/l. This translates to about 0.65% body fat with Siri’s equation
(ignoring the uncertainty inherent in that equation, which is a constant bias
accross measurements for one person on any given day).

Note that I give ρ_w this time, instead of whisking it away with a
magical 1 kg/l. I picked an average value between 72°F and 84°F (most pools are
in this range), with an uncertainty (due to water temperature) of about 0.001
kg/l. If you use 1 kg/l instead you are introducing a bias of about 0.9% body
fat. So I was wrong about that being insignificant.

Now, I found a better estimate
(why better? because it seems to come from a more reputable source than
Wikipedia) for residual lung volume: v_r = RV = 0.24 VC. So I may
have overestimated my RV last time by ½ liter.
(Update: I think that must be a typo on that page, they probably mean 24% or 28% of total capacity instead. This fits in much better with the rest of the literature that I have found, e.g. Quanjer and Paoletti.) That seems like a generous
uncertainty measure for RV, too. With that uncertainty factored in, we get an
uncertainty of about 2.1% body fat, or about 5% is you are on the slight side of average (the less you weigh, the more difference that 1/2 liter makes).

So, Dad, let’s bump your score up by about 1% for the density of water and then
tack an uncertainty of 2% onto it, you have a body fat of 26.3% ±2%. I’m no
expert on using calipers, but one paper’s
abstract indicates that the
skinfold method uncertainty is about 3%. I’ve seen 10% tossed around casually
too, but have no reliable source to back that up. That puts the two methods
within the appropriate reach of eachother, which is heartening. It’s
interesting to note that BMI is overestimating Dad’s fat, because he’s more
lean than the average couch potato. Imagine the difference if the subject were
someone completely nuts, like a young triathlete, who has body fat of about
15%. Even better, if you are such a nut you could do the experiment and post
your results (and BMI) here as a comment for us to see.

If you look over at that graph you’ll see that I’ve gone from 120 kg to 117.2 kg in 4.5 weeks. Enough that I think we can say it’s not a fluke and I can blog about it in good conscience.

I’ve been doing the Shangri La “diet” for a few
weeks now. Redbeard blogged
it when I told him
about it when I first read about it on the Creating Passionate Users
blog.
It’s a strange but scientifically-based diet based on two fairly established
theories: first that your body has a body fat set point which works like a
thermostat, and second that your body learns to associate calories and taste,
raising the set point when you eat food that has been associated with calories.

I’m not going to go into the why in detail, since you can learn that at Seth
Roberts’ site. He wrote a book
about it too, but the diet is simple enough that the mechanics can be explained
in one sentence.

Every day, ingest 4 tablespoons of extra-light olive oil or sugar dissolved
in water at least one hour away from tasting any food (or anything else with
taste, like toothpaste). I like to have a tbsp of ELOO followed by a chaser of
a quart of water with a tbsp of fructose (lower glycemic index), twice a day.
The sugar water is effective at getting the oiliness out of your mouth quickly.
But when I’m in a hurry I’ll take 2 tbsp of oil, or sometimes if I’ve been
procrastinating it all day I’ll take 4 tbsp of oil.

Your appetite will reduce and you will lose weight on your body’s terms simply
by not being as hungry. I’ve read blog entries about how your appetite totally
disappears blah blah… well mine didn’t, but I’m 6′4″ and we wouldn’t really
expect that now would we? I do feel somewhat less hungry, or at least full
sooner. Is it a placebo effect? Time will tell. If time doesn’t tell then I’m
tricking my body into a better weight, and I’m ok with that. (As an aside, how
do you control for a placebo effect when a standard placebo (sugar pill) would
actually be following the diet? ;-)

The big question is, is it sustainable? I mean, do we really want to be
drinking olive oil the rest of our lives. Well, drinking olive oil isn’t that
bad after you get used to it. No, really. Sugar water is actually more of a
pain because if you care about not messing with your blood sugar you have to
drink it slowly. In the book he talks about someone who does the diet down to
his optimal weight, then stops and slowly rises back up 10 pounds or so, then
goes back on, etc. I could live with that, even if I couldn’t live with it
every day which I think I could. Besides, I predict that if this diet works for
a lot of people, and I think it will, then it won’t be long until someone makes
a tasteless pill with enough calories that doesn’t mess with your blood sugar,
and it’ll be just like taking vitamins.

My body is going on a diet (not me, but that’s another post), but we all know
it’s no fun to go on a diet unless you get a nifty digital scale and make cool
graphs of your progress. Over on the left you’ll see my cool graph which I
generate with a small ruby script (less than 60 LOC) and even smaller shell
script. The use case is simple. Every day after weighing myself I do simply
this:

mg $my_weight_today

You too can make cool graphs if you mosey on over to my src page.