Personal Science Week - 241107 Body Scan

My experience with DEXA, plus more links

DEXA is a technology that lets you quickly and painlessly measure your body’s relative bone, muscle, and fat composition.

This week I summarize my experience with a DEXA full body scan.

DEXA (Dual-Energy X-ray Absorptiometry) is one of the most accurate ways to measure body composition, including bone density, lean muscle mass, and fat distribution. While originally developed to diagnose osteoporosis, this medical imaging technology has become increasingly popular among personal scientists who want precise data about their body’s makeup. 

The scan works by passing two different energy levels of X-rays through your body. Since different tissues absorb radiation differently, the machine can distinguish between bone, muscle, and fat with remarkable precision. The process takes less than 10 minutes and is completely painless. Just wear ordinary or workout clothing (no metal tags or zippers) and lie flat on a comfortable open table while the machine does its thing. 

I’ve known about DEXA for a long time, but I never bothered because the couple-hundred dollar price seemed too high for somebody like me who’s not obsessed with knowing about every gram of fat or muscle on my body. But after a friend gifted me a session, I learned how wrong I was.

First, the price. Don’t pay the exorbitant charges from a medical imaging center. Instead, look for a wellness center or one of the growing number of fitness centers that offer the service. If you live near a BodySpec office in Seattle, California, or Texas, the cost is only $60 ($50 if you use the discount code they gave me). They offer all kinds of incentives to book regularly: scans are only $40 if you sign up for a monthly plan. 

BodySpec has a fantastic booking system that makes it easy to make an appointment online. I had no trouble scheduling one the same day at a location only a few miles from my house. 

They say it can take a day to get the results, but everything is computerized, so I had mine within an hour of leaving their center. It looked like this:

I’ve always been pretty thin, and my body mass index (BMI) is well within normal ranges, so I knew my DEXA results wouldn’t suddenly peg me as obese. In fact, I’m pretty low on visceral (aka “bad”) fat.

But the other numbers were a big surprise—and a wakeup call. Since DEXA is fundamentally a tool for osteoporosis screening, that low bone density is something I’ll take very seriously. In fact, I’m disappointed in myself that I didn’t already know this. I’m pretty active—many hours of vigorous exercise per week—but I’ll need to be extra careful going forward to avoid fractures and other bone issues as I get older.

One important caveat: the percentages on the BodySpec reports are apparently compared to the tens of thousands of other BodySpec users—not the general population. If their user base skews toward healthy and fit people, that makes a big difference (I’m trying to confirm this with the BodySpec team and will let you know what I hear).

Meanwhile, these results have given me some valuable feedback about my unique physiology that has already got me thinking about making changes to my diet and exercise plans. For example, it’s clear that I’ll need to significantly increase my protein consumption, up from the roughly 90g / day that I’ve had for years, and maybe increase my overall daily calories as well.

Look for many more conclusions in the coming weeks as I study my results more closely.

Personal Science Links of Interest

Speaking of body parts, here are a few additional sites that curious personal scientists should know:

For about $1800, you can order a real human skull from skullsunlimited.com. David Lang explains more about why you might want to do that.

If you or someone you know dies in Oregon, Washington, or Northern California, you can get your brain preserved for free by the non-profit Oregon Brain Preservation. It ordinarily costs about $1000 for transportation, but they’ll waive the fees if you let them take a biopsy first. Note: this is for chemical preservation; it’ll cost $10K or more if you want to be frozen. (via LessWrong)

PSWeek reader Zaid K Dahhaj has a list of aspects of the body designed to sense and use light (paywall). Circadian biology, affected by sunlight, probably has a bigger effect than we realize.

People Science is looking for volunteers to try a new Lactiplantibacillus plantarum probiotic. You’ll get free supplements to try for 7 weeks, and the option to try a sub-study to test your urine. You have to wear an Oura ring nightly, but it’s unclear if they supply that or not. I tried to enroll but was rejected so my guess is that you’ll need to have pretty serious sleeping issues to qualify.

If you like cats, a French physicist has published the physics of cat movement in the academic paper On cat–human interaction from the viewpoint of physics: An equation of motion. If you’re into this sort of thing, this is a good opportunity to brush up on your differential equation skills.

Don’t forget to get on the mailing list for A Biohacking Future by Shelby Newsad at Compound VC. I’m told they’re sending print copies now that they’ve recently released their Years 2027-2029 speculations of what to expect from all the cool stuff happening in biology in a surprisingly short number of years.

About Personal Science

Professional scientists do science as part of a job, but there are many advantages to science done for personal reasons. You can study whatever is most important to you, for example, and you can start immediately. No proposals to write, no bureaucratic gatekeepers, no years of waiting on biased and petty peer reviewers. The important thing is to remain open-minded and curious, but also skeptical about whatever you find.

Personal Science Week is our collection of ideas and thoughts we think will be interesting to anyone who wants to be a personal scientist. Subscribe to receive a post every Thursday. Paid subscribers get additional, more controversial posts from our Unpopular Science series, including last week’s issue about politics.

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