My BMI calculator has me inching towards despair

I’ve become obsessed with my BMI. For those of you who don’t know, it stands for body mass index and is supposed to be a more reliable way of assessing whether you’re a healthy size than weighing yourself. It’s calculated by dividing your weight by the square of your height and is expressed as kg/m². If your BMI is under 18.5 kg/m² you’re underweight, if it’s over 25 kg/m² you’re overweight, and if it’s above 30 kg/m² you’re obese. The sweet spot is anywhere between 18.5 kg/m² and 25 kg/m².

As regular readers will know, I’m on a diet. At the beginning of the year I was nearly 13st and I’m trying to get down to 11st 7lb. So far, so good, with only 4lb left to go. But infuriatingly, my BMI stubbornly refuses to dip under 25 kg/m², so I’m still technically overweight. At least, that’s what my fancy new Nokia Body+ scale tells me. I bought this scale because, in addition to recording your BMI alongside your weight, it syncs with various apps on my phone and enables you to track your weight loss —which I’ve been doing every minute of the day. There’s one in particular called MyFitnessPal that I stare at almost continuously.

The weird thing is, when I plug my height and current weight into the BMI calculator on the NHS website, it says my BMI is 24.7 kg/m², which is just on the right side of the healthy/overweight border. But the scale still insists it’s 25.1 kg/m². Why the discrepancy? After puzzling away at this for hours, I eventually figured it out. It’s because when I entered my height into the scale I wasn’t able to include half-inch units. I’m 5ft 8.5in, but rounded this down to 5ft 8in. That vital half-inch is what makes all the difference.