I love the digital scale I have. It’s accurate, easy to read, and has a number of interesting features, not the least of which is a body fat measurement.

Throughout the last several months, as I have been engaged in my 40-pound weight loss, I have noted, but not really paid much attention to, the body fat percentage on the scale. I have seen it go down since the summer. I don’t really remember where it started, but I have seen where it’s ended and lately, it’s been reading around 25.3%.

Not having thought about it too much, I’d started tracking the numbers along with my daily weigh in and entering the information on LoseIt! and FitBit. But then I noticed something odd—there was something not quite right about these numbers.

I have a vague recollection that my body fat was registering in the high 20’s or around 30 when I began this enterprise. If my scale was now reading 25.3% then that means that over the last several months, I’d decreased by body fat by a sixth.

But that math doesn’t add up. If I was 30% body fat at 222 pounds, then fat accounted for 66.6 pounds of my weight. If I am 25% body fat at 182 pounds, then fat accounts for 45.5 lbs of my current weight. That’s a net decrease of 21 pounds.

But I lost 40 pounds. What were the other 20 pounds of? Not muscle—if anything, I’ve gained muscle mass. Water, maybe, but that seems unlikely: each pound of fat would have to have held a pound of water–that’s two and a half gallons of water for 20 pounds. I was also tipped off by the chart on my Fitbit page which suggested that I’d actually decreased in lean body mass—something that could only be possible if indeed I had lost 20 pounds of non-fat weight.

Now, I had had a goal on my LoseIt! app of reducing body fat, even if I hadn’t been paying it much mind. Initially, I’d been aiming for 23%, because I’d read somewhere that that was the upper limit for what my body fat should be. But there were two things wrong that that: (1) that still seemed high, and (2) I was struggling to move my body fat by more than 0.1 or 0.2% and could never go down below 25.2%. That goal seemed unreachable based on my current rate without another significant weight loss.

So, I went online to find out what an ideal body fat percentage is (it’s around 16.9-20.7% for men of my age), and to find out how I could accurately measure my own.

One very helpful website, discussed the various body fat categories and provided very helpful pictures of what each looked like. The first thing I noticed was that the picture of the percentage range where I presently believed myself to be looked a lot more like where I had been 40 pounds ago.

The site was also helpful in describing the ways of measuring body fat and indicated that electronic scales that sent an electric pulse through the body were among the least accurate ways of measuring body fat. The absolute best method is a buoyancy method that uses weight and water displacement, but a close second is the use of calipers.

So, I looked online: where can I buy calipers? Well, Amazon, obviously; but is there anywhere I can walk to that sells them? Yes, GNC. And they’re two blocks away. So I headed on over to the GNC on Connecticut Avenue and purchased a pair.

They work by measuring the thickness of the fat pinched at a particular place on the body—the suprailliac—a spot about an inch above your right hipbone. Scientists have done extensive experimentation to determine that the measurements taken at that spot on the body most closely correlate with body fat percentages established through buoyancy methods. As a result, using calipers on this part of the body is the most reliable, inexpensive way to measure body fat.

Once I got home, I read through the directions, found my suprailliac and measured. I took multiple measurements in case there was a variation. On balance, I measured 9mm. Then I took to the included chart to find out what that meant.

14.8%

It was so much lower than what my scale had been telling me. And so much closer to where I felt I had to have been. It was an amazing feeling to know that I was in the healthy range here, too.

Being in the healthy range of things has been new for me. But in early December 2017, I crossed into the healthy weight range (below 184), the healthy Body Mass Index (BMI) range (under 25), and now, I’ve learned, also into the healthy body fat range.

These six months since I began this weight-loss again in earnest have been so rewarding because they have been successful. That dopamine rush I get every time I step on the scale and the number not only begins with a ‘1’ but continues with an ‘8,’ is so powerful that it spurs my continued energy to maintain my weight, my healthy habits, and my tracking.

These calipers were a few dollars. But the value they have given me in furthering that sense of accomplishment and wellness has already been well beyond that.