We Tried It: What Can You Learn From a Body Composition Test?

By Lisa Elaine Held

For 13 years, Lara Metz, RD, NLC, weighed her clients on a standard scale. As a nutritionist, it was a standard practice, but it left her unsatisfied in terms of how it was really helping people get healthier.

“That’s not going to tell me anything other than a number,” she says, “and what does that number mean?”

Instead of ditching numbers altogether, she decided to get better ones. A few months ago, Metz invested in a machine called the InBody, which she now uses to measure clients’ body composition, from your visceral fat level to the amount of muscle in your right versus left arm. “I think it can add value to the practice and give clients way more information, and so far they’re loving it, and I’m loving it,” she says.

We stopped by her Manhattan practice to find out more and give the test a spin.

body composition test

What Is a Body Composition Test?

The InBody uses technology called “bioelectrical impedance analysis,” which sends a small alternating current through your body to measure resistance. Muscle, fat, and water, for instance, all have different conductivity, so it’s able to evaluate how much of each it’s encountering.

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In addition to good old weight and BMI, your body composition analysis reports your total body water (intracellular and extracellular), skeletal muscle mass, and body fat mass. It further breaks down your muscle mass into how much is in each arm, leg, and your trunk.  Finally, it tells you your visceral fat (the deep abdominal fat that surrounds your organs) level, and your basal metabolic rate (how many calories your body burns at rest).

body composition test

What Is a Body Composition Test Actually Like?

Here’s how it works: You’re fully clothed but barefoot. You wipe your palms and the bottom of your feet with a wet wipe and then step onto what looks like a tricked-out scale. Your feet are placed on top of metal sensors and then you hold metal sensors that are at the end of “arms” in front of you. (During the test it kind of looks like you’re awkwardly holding hands with a robot.) You have to stand completely still and not talk or laugh (we found this challenging) while the analysis is in progress, but it’s over in just 30 seconds. Then, a couple of minutes later, a detailed paper with all of your details prints out.

Metz offers the test to all of her clients if they’re interested, and then she re-tests them about every two months. If you keep testing sooner than that, you’re unlikely to see results, she said, because changing your body composition takes real time.

body composition test

Is a Body Composition Test Helpful?

First of all, it’s definitely interesting to just suddenly know the exact makeup of your body. For me, it was mostly a validating experience. As health editor, I eat well most of the time and exercise often, so my numbers generally painted a picture of someone doing a decent job at living a Nutritious Life (somehow despite my love of wine!). My body fat and visceral fat numbers were low and my body was mostly balanced from side to side (more on that in a minute). While my muscle mass was in the healthy range, it was lower than I would like it to be, which made sense because I used to do more strength training and have been trying to get back into it.

RELATED: 5 Yoga Routines That Build Strength

body composition test

I was mostly fascinated by the information, and for someone going to a nutritionist to work on making changes, I could definitely see how it could be useful. Maybe you think you need to lose a certain amount of weight, for example, but then you find out you’ve got a lot of muscle mass and not as much body fat. On the flipside, if you find out you’re carrying a lot of visceral fat, that can be genuinely dangerous. “It’s okay to have a little bit of fat around your organs because you need it for insulation, but if you have too much it can be an indicator of health problems like cardiovascular disease or diabetes,” Metz explains.

And those side-to-side numbers: If you discover your right and left leg are very unbalanced in terms of muscle mass, that’s a big risk factor for injury as you age, so you could bring those numbers to a trainer and work on balancing things out.

Finally, Metz says one of the biggest benefits she sees is that while her recommendations as a nutritionist don’t generally change based on the numbers (she’s always going to work on getting more quality whole foods in your diet, teaching portion control, and helping you learn to listen to your body), her clients are motivated by the detailed analysis, since they can see progress on paper. “It’s giving clients tangible numbers to look at and helping them reach their goals in a more concrete way, rather than something more abstract,” she says.


(Photos: Colleen Sheehan)

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The Nutritious Life Editors are a team of healthy lifestyle enthusiasts who not only subscribe to — and live! — the 8 Pillars of a Nutritious Life, but also have access to some of the savviest thought leaders in the health and wellness space — including our founder and resident dietitian, Keri Glassman. From the hottest trends in wellness to the latest medical science, we stay on top of it all in order to deliver the info YOU need to live your most nutritious life.

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