The 4-Hour Body_ An Uncommon Guide to Ra - Timothy Ferriss [22]
If you want to skip directly to the actions, jump to “Starting Your Physical GPS” on this page. In fact, I suggest this for the first read through.
Choosing the Right Tools
I used to have a signature move while driving.
About a quarter-mile or so before arriving at my hard-fought destination, often within 200 feet, I would come to the unwavering conclusion that I’d gone too far. Then I would U-turn and drive in the opposite direction, only to repeat the drill like a dog tethered to a clothesline. Best-case scenario, this shuttle run doubled my travel time. Worst-case scenario, I got so frustrated that I abandoned the trip altogether.
This is exactly what most people do with fat-loss and exercise.
Using a blunt instrument like a scale (the equivalent of the odometer in my example) people often conclude they’re not making progress when, in fact, they are making tremendous progress. This leads to a musical chairs of fad diets and demoralizing last-ditch efforts that do more harm than good. To hit your target 20-pound recomposition, you’ll need to track the right numbers.
The scale is one tool, and you should use it, but it is not king. It can mislead. Take this unedited feedback from Angel, who was two weeks into the Slow-Carb Diet at the time (see “The Slow-Carb Diet I and II” chapters):
After my cheat day on Saturday, I gained 1 pound which is normal for me … week two, I lost that 1 pound. I didn’t lose any [additional] weight on week two, but I’m not discouraged. I did manage to lose in inches. I lost ½ an inch off my hips which is absolutely great. I lost a total of 1 inch off my thighs. Not so shabby either. So that’s a total of 1.5 inches for the week. I’ll take the inches. The grand total of inches lost from Day One: 5 inches … Yippee! No exercise either.
My driving issues ended when I bought a GPS device.
The GPS fixed my problem because it could answer the simple question: was I getting closer to my destination?
In body redesign, our “destination” is a better ratio of body composition, not weight.
How much of you is useful muscle and how much of you is useless fat? Our constant companions will be circumference and bodyfat measurements. By the end of this chapter, you will have a starting point for your own physical GPS. This will guide you to your 20-pound recomposition goal.
Circumference is easy enough: use a tape measure. We’ll cover the details at the end of this chapter.
But how do we actually measure bodyfat percentage?
It turns out, there are a lot of options, and the most common are the worst.
Skinning the Cat
In one 24-hour period,4 I took more than a dozen bodyfat measurements using the easiest-to-find, as well as the most sophisticated, equipment available.
Here are some of the results, from lowest to highest:
7%—3-point with SlimGuide calipers
7.1–9.4%—Accu-measure
9.5%—BodyMetrix ultrasound
11.3%—DEXA
13.3%—BodPod
14.7–15.4%—Omron hand-held bio-impedance (second value after drinking two liters of water in five minutes)
15.46–16.51%—4-site SlimGuide calipers
The range is 7% to 16.51%. So then, which of these bad boys is accurate?
The truth is, none of them are accurate. Moreover, this doesn’t matter. We just need to make sure that the method we choose is consistent.
The following table shows the various techniques I considered, ordered from most to least error-prone.5
Provided by Luiz Da Silva, PhD., scientific advisory board, UC Davis National Science Foundation Center for Biophotonics Science and Technology.
After dozens of trials with multiple subjects, and taking into account both constancy and convenience (including cost), there were three clear winners:6
1. DEXA
2. BodPod
3. Ultrasound (BodyMetrix)
The Top 3
DEXA
Dual energy X-ray absorptiometry (DEXA), which costs $50–100 per session, ended up my favorite, as it is repeatable and offers valuable information besides bodyfat percentage. The GE Lunar Prodigy, the machine I used, is designed for bone density testing and splits the body into different zones:
My DEXA scan image.
If