13 Weeks: How Scales Lie

Week 4 of my second 13 week season; low carb diet and more exercise, tracking my weight, blood glucose, and body fat. You can follow me at my 13 Weeks Facebook page for daily updates, and you can join Fitocracy and follow my daily exercise.

I haven’t published new charts recently, so I think it’s time. Here’s the first one, my weight.

OH, NOOOOOES! My weight is going up! I’m a failure! Eeeek!

Well, maybe not, although certainly if all I was tracking were my weight I’d be mildly hysterical. (And I have to admit I get qualms looking at it this time, even though I swear I’m not primarily interested in my weight. But 50 years of dieting doesn’t go away quickly.)

The thing is, that weight in general isn’t really our primary interest. I asked whether weight itself was a primary concern over at my Facebook page, and got a lot of different interesting answers; almost none of them included weight. “Feel better”, “better health”, “more attractive”, “sexier” all did show up. Now a couple of people with bad knees and backs did say weight in itself was a problem, but for most people it’s more a symptom of something else that troubles them. Certainly so with me — blood sugar, health in general, and as I realized during the first 13 weeks, simply feeling ugly and disgusting were my major issues.

What people use as a proxy for all this is weight, of course, and especially with daily weighings, this can be very disheartening.

What’s worse, I’ve been at least as diligent with the diet — in the last full week, according to LostIt!, I’ve been 8200 kcals in deficit, with an average of about 9g carbs a day net of fiber. Being diligent with the diet isn’t so awful, but still I’d sure like a chocolate bar or a plate of spaghetti sometimes. In anything, I’m doing better with the diet plan that in my first 13 weeks.

Add to that I’ve been pretty diligent with the exercise — not every day but at least five days a week (I’ve got more to say about the exercise, below) so I’m lots more active than I was in the first 13 weeks — and probably more than I’ve been in the last 13 years.

But still, I’m actually gaining weight.




Now, repeat after me, this is not about weight. (I’ve been repeating it a lot the last couple weeks.) Let’s start looking at some other measures. Here’s my blood glucose:

Obviously the variance is pretty wide, but look at three things: the highs are getting lower, the lows are getting lots lower — if fact I set a new record low this week, of 91 mg/dL — and the trend line slopes sharply down. Glucose looks pretty good, and my most recent A1c of 5.9 confirms it.

Now, let’s look at body fat.

These numbers are a bit hard to interpret, since body fat by the body-impedance method varies so much randomly, but the trend line is definitely down after four weeks. But there are also other measures of body fat, the easiest being the Army method, which uses an empirical formula to compute body fat from neck and waist size.

So I took some measurements again, something I haven’t been good about doing weekly because I wasn’t seeing much change.

Date Neck(in) Waist (in) Army bodyfat %
2012-11-04 20 48 31
2013-02-01 18 46 31
2013-03-02 18 43 26

Here’s the result: In the first 13 weeks I lost two inches on my neck and two inches around my waist. In the following four weeks, I’ve lost another 3 inches (a total of FIVE inches) around my waist.

Obviously, I like the Army’s numbers better, so let’s use them — according to the Army, I’ve lost 5 percentage points of my bodyfat over the last four weeks, with my weight remaining stable. (Other methods give me somwhere around 29 percent, which is the most common value from the Withing body impedance too.) My weight is around 273, and 5 percent of 273 is 14 pounds close enough.

Two have lost that much bodyfat, and still gained rouhgly 2 pounds over that four weeks means I’ve exchange some amount of bidy fat for muscle, while alsobeing around 32,000 kcals in arrears for that whole four weeks. is that even possible? Or are the measurements all wrong?

It turns out it is indeed possible. First of all remember that adding a pound of muscle changes the body composition exactly as much as losing a pound of body fat — so trading a pound of fat for a pound of muscle changes the percent body fat by twice as much as either one alone. So one possible solution to explain a loss of what seems like 16 pound of bodyfat is that I actually lost 8 lbs of fat and gained 9 lbs of muscle (accounting for the slight weight gain.)

There’s another fact to remember, though — we concentrate on the rule of thumb that a pound of fat has 3600 kcals, and forget that an equally valid rule of thumb is that a pound of muscle has 1800 kcals. So it’s mathematically possible that a pound of lost fat could go into two pounds of gained muscle.

It doesn’t really happen that way. Back when I did biomedical simulation, we’d build a compartmental model and write down a bunch of difference equations and then solve it to see what really accounts for this — which I promise I won’t — but intuition says it doesn’t have a unique solution anyway. But what’s clear is that adding the exercise program has caused me to add muscle as fast, or even a little faster, than I’m losing fat.


Which brings us at last to the exercise program. David Steinberg’s series on “Charlie Martin, Late-Blooming Athlete” has been suggesting some specific things recently, some of which I’ve actually paid attention to. So what I’ve been doing (and you can join Fitocracy to see the specifics day to day) is doing a fairly heavy routine of squats and deadlifts, alternating with Tabata-protocol with lighter weight, so I’m averaging about 175 Fitocracy points a day. (This takes into account some of the days I’ve missed; as you can see from my Seinfeld calendar as of February 28, I’m not hitting every day.) I’ve been experimenting with presses and press-like things, and have recently added one-arm rows, so I’m at least beginning to approximate what David is suggesting.

Damn if it doesn’t seem to work.

And now, the part where we tabulate. Here’s the weekly data (7 day averages and weekly totals) from the whole 4 weeks. I’ll include an updated table every week from now on.

Date 7 day Weight 7 day Glucose 7 day Bodyfat Sum Fitocracy Points Weekly Fitocracy Points
2013-02-01 272.50 116.43 33.1 447 447
2013-02-07 272.63 114.57 30.79% 1881 1881
2013-02-14 271.91 110.43 30.36% 2606 725
2013-02-21 273.79 115.29 29.16% 3775 1169
2013-02-28 274.44 104.00 30.00% 4929 1154
Δ since 2-1 1.94 -12.43 -3.10% N/A N/A