Measuring Body Fat Accurately: Is There Such a Thing?
There are a lot of ways to measure you body fat levels: Bod Pod, underwater hydrostatic weighing, skin-fold calipers, bio-impedence, DEXA, to name a few of the most common. Unfortunately, most of the tests can be inaccurate, to wildly inaccurate. What do I mean by this? Here's an example: you just started a brand new strength training routine and you want to know if you've gained any muscle. In this instance, gaining even two pounds of muscle would be considered a success (advanced trainee, one-month into a new routine). How reliable do you think ANY of these tests are in showing a one or two pound increase in muscle? Not very. The majority of these tests do okay in showing major changes, i.e., losing ten pounds of fat or gaining eight pounds of muscle, but none excel at showing small increases or decreases. In my experience the vast majority want to know if they've made small changes. They're told that these tests accurately show muscle and body fat levels. Accurately means showing even a minute change on body composition, or that's at least implied. This just isn't the case. There is no test out there that will accurately, 100% of the time show if you've lost a pound of muscle or gained a pound of fat. The only way to get even close to knowing this is to literally perform an autopsy on a person and weigh everything out. No joke. I'm certain that no one is going to sign-up for that "body fat test."
Everyone has their own personal favorite but a lot of this has to do with what their facility provides. If the facility provides Bod Pod testing, the employees will rave about how accurate it is. If the facility does skin-fold caliper testing, the same thing will happen: it's the greatest thing since sliced bread. Just keep in mind that they're trying to sell you something and they likely don't have experience with multiple means of testing body fat. Also: just remember that all of these tests show what I call generalities. They're not literal numbers. It's not actually weighing your muscle. It's not actually analyzing your fat. Like I said, the only way to do that is to do some insanely invasive medical procedures.
The best way to think about these tests are like forecasts. A forecast looks at the data and then extrapolates likely data, or trends, from it. So, a general forecast is what you're likely to expect but we've all seen weather forecasts that have been wildly inaccurate. I've seen this firsthand. I've had several males - all of whom were in fantastic shape - come around 1.0 to 1.5 % body fat when tested in a Bod Pod. Did I retest them? I sure did and the results came back nearly the same. I've also seen the same thing in lean females: numbers that are just impossible. Numbers that even the test subjects thought were ludicrous.
Do you really want to pay money for a forecast? There are websites that show you what men and women of certain body fat levels look like. Go to one of those and compare your physique to the ones online. Maybe even take a photo of yourself and then put it side-by-side next to the online person for a true comparison. This is way cheaper and really just as accurate as any of the other body fat tests.
My ultimate recommendation? I call it the Jeans Test. We all have a pair of jeans that we've had for a couple of years. We know exactly how they fit, the tightness around our waist, and what belt buckle setting we have for those pants. Do this: try those jeans on and if they are looser in the waist, then you've lost body fat. If they fit exactly the same then yep, you guessed it, you're exactly the same. If they're tighter around your waist, then you've added body fat. This "test" doesn't address muscle gain/loss but simply look in the mirror. You don't need an expensive test to tell you if you've gained a few pounds of muscle. Do you look more muscular? Are you lifting more weight or doing more reps with the same weight than before? You're likely gaining muscle. Simple and easy.
And remember: there are no competitions for body fat. Bodybuilders and figure shows aren't decided on body fat levels. Crossfit competitions aren't based on who has the lowest body fat. Your health insurance provider doesn't ask for your body fat percentage. Before you run that 5K, no one demands to know your body fat percentage. What I hope matters to you is your health and well-being and not some ambiguous number listed as your body fat.