'Every now and again, I need something to come along and shock me into being more active. For better or worse, this was it'
What is it? Essentially a set of home scales that present you with a range of other data about your body.
How much does it cost? I used the Tanita BC-731, which costs around £45.
What does it promise? Knowing your weight is one thing. A body composition monitor, however, will also present you with your BMI, your bone mass, your level of visceral fat, your body fat percentage and your metabolic age. This one even ranks your physique, which seems ever so slightly cruel.
What's it actually like? Absolutely, overwhelmingly, soul-destroyingly miserable. I thought I was in decent shape. I mean, sure, I probably haven't done as much exercise as I should over the last couple of months, but I thought I was doing OK. According to the magical Tanita and her analytics, I'm not. I'm heavier than I thought. I'm more solidly built than I thought. I have the body fat percentage of an obese man. My metabolic age is that of someone 15 years older than me. I immediately hopped on it again, assuming that the whole thing was rigged specifically to make me feel awful. Although the numbers were slightly different the second time around, they were broadly the same. Every now and again, I need something to come along and shock me into being more active. For better or worse, this was it.
Best and worst bit Did you see what the machine told me? I'm basically the world's lardiest git. This machine is just a really expensive way to make sure you feel terrible for the rest of the day. But did I need to hear this? Probably.
Is it worth it? Begrudgingly, yes.
Illustration: Son of Alan for the Guardian
