The Pros (and Cons) of Biometrics

The Pros (and Cons) of Biometrics

“Biometrics” is any of the stuff you can measure about your body, but in the fitness world usually refers primarily to bodyweight, bodyfat percentage, and muscle mass (and occasionally to circumference measurements). And let’s get this out of the way right up front, body image stuff in the USA in 2025 has the potential to be a GD nightmare.

There are all kinds of reasons not to track biometrics.

1. They have no bearing on your intrinsic worth as a human being.
2. They are necessarily impermanent. They change as you age, they change with injury, they change with life seasons.
3. A ton of marketing is geared to keep you obsessed with them (and with bodyweight in particular) to an unhealthy degree.
4. They do a decent job describing how your body looks, but they don’t at all show you what your body can do.

There are plenty of people who live long, healthy lives who never measure their bodyweight, bodyfat percentage, muscle mass, or circumference. It is not remotely necessary for health or wellness.

But ignoring biometrics really works best when you’re also totally satisfied with how your body composition.

If you’re not satisfied with your body composition, ignoring biometrics is a little tricky.

It’s kind of like being broke and never checking your bank account because you’re scared of what you’ll find there. Totally understandable. But at some point, if you want to stop being broke, you have to grit your teeth and start looking at how much money you have.

If you want to change your body composition, you really need to have some way to measure whether or not what you’re doing is working. Now, there’s a fine line here between measuring and falling back into the obsessive shame cycle that feeds a whole industry (a coach can be very helpful here with deciding what to measure and contextualizing it so you don’t feel insane).

But it’s very difficult to know if your plan to change your body composition is working if you don’t have some objective measurement. (Side note: Determining whether or not it’s working by how you feel is unreliable. You will feel like your body isn’t changing if you’re sad, or if you’re stressed, or if you’re insecure. That may or may not be an accurate description of the facts).

Reasons to track biometrics include:

1. An objective reflection of progress. This is just data. It’s neither good nor bad.
2. The ability to see trends (and then adapt or tweak the plan).
3. The ability to see context. A 2lb weight gain can feel like the whole ship is going down if it’s the only data point you’ve had in a year. But likely, you gain or lose 2lbs multiple times every month without any noticeable effects.

Biometrics are just information. They describe what’s happening. And whether or not you choose to track them is a totally personal thing that does not have a right or wrong answer. Because ultimately, like with nearly everything in fitness (and probably in life too), the answer to the question, “Should I…?” is “It depends.”

If they stress you out, scrap them. They’re not necessary. If you’re totally happy with where you are with respect to body composition, ignore them. They have no bearing (by themselves) on what your body can do or how you feel.

But if you’re trying to make a change, it’s good to know what your starting point is. Just make sure you have a coach or trusted friend to help you contextualize.

Data is a tool. And just like any other tool, it’s good for some jobs, not for all jobs. But if it’s one you think might help you, put it to work. And let us know how we can help!