LinLog

So here's a random fitness-related link.  It's a handy page I found for doing visual body fat comparisons.  I particularly like this one because (at least for the men's section) a bunch of the pictures are of the same guy.  Apparently he must have lost a bunch of weight and kept good track of it.  That makes it much easier to see the differences in physique than when you're looking at different people with different sizes and shapes.

If you're not into fitness, you might not be familiar with body fat measurement.  Body fat percentage is one of those metrics that are handy for gauging your fitness level.  It's basically just the percentage of your body weight that consists of fat.  If you don't train, then just tracking your weight is fine, but once you're lifting weights or doing other strength training, you're going to build muscle.  Since muscle is more dense than fat, it makes weight tracking less reliable - you can get into a situation where you're getting thinner, but are actually gaining weight because you're burning fat and building muscle.

There are a number of ways to measure body fat: there's the DEXA scan, which stands for dual energy X-ray absorptiometry and is considered the "gold standard"; there are multiple techniques using calipers to measure skin folds; and there's the seriously low-tech method of eyeballing it, i.e. using comparison pictures. Of course, none of these measurement techniques is exact.  Even the DEXA scan is just an estimate that can be influenced by a variety of factors.  The only 100% accurate way to determine your body fat percentage is to excise every gram of fat from your body, weigh it, and compare that to your total weight - which can't be done without killing you.

Looking at pictures is the method I use.  It's obviously the least accurate and the least precise, but it has the benefit of being by far the cheapest and easiest.  I mean, you're just looking at pictures on the internet, for crying out loud!  And for my purposes, the exact number doesn't really matter anyway.  It's more a reference point for helping to figure out what weight changes mean and where my general fitness level is.  It's nice to have a general idea, but it's not important enough to me to spend significant time or money on it.  It's just one metric among many.  How useful it is depends on your needs and goals.