The scales: the moody liar in the bathroom

Bathroom scales are a useful tool with the personality of a wind-up merchant. Here's how to use them without letting them use you.

Meet the Doctor

Meet Dr Shamington the Third of Brunswick. He lives on your bathroom floor. He went to a very expensive school, learned nothing, and has opinions about you.

On Monday he tells you you've put on two pounds. You haven't. You had a salty curry and he knows it.

On Thursday, after a hot day and a long walk, he tells you you're a Greek god. You aren't. You're thirsty.

He's wrong in both directions, often before breakfast. So we don't take his word for anything, and he only gets to speak once a month.

Give yours a name. Something you'd never trust with your car keys. When the number's bad, it isn't your verdict. It's just the Doctor, being the Doctor.

Why the number wobbles

Your weight isn't a fixed number. It moves through the day and across the week with water, salt, what you've eaten and what you haven't yet said goodbye to. Studies that track people's weight find it tends to creep up over the weekend and drift down during the week.¹ A salty takeaway can hold extra water overnight. A hot day can take it off again. None of that is fat.

Once a month. Same rules.

Weighing yourself does help some people. Reviews of the research link regular self-weighing with better weight loss, so we're not saying scales are evil.² But if every wobble ruins your morning, the daily number is costing you more than it's telling you. So in Basic Training, the Doctor speaks once a month.

• Same day each month. Put it in your phone calendar.
• First thing in the morning, after the toilet, before you eat or drink.
• Same scales, on the same hard floor. Scales on carpet make things up.
• Same clothes, or none. Your call. The Doctor has seen worse.
• Write the number down. Then put him back under the sink.

Better ways to measure

• Your belt. Which notch? It's the most honest object in your house.
• One tight pair of trousers. Try them on once a month. No sucking in.
• A tape measure round your waist at belly button level, once a month.
• The stairs test. How many flights before you're puffing?
• The talk test. Can you walk briskly and still hold a conversation?³
• Everyday life. How you sleep, how you feel at 3pm, and whether you can carry all the shopping in from the car in one trip. Some heroes already do this, at great cost to their fingers.

Progress photos work for some people. If the mirror chapter sounded a bit familiar, skip them. A tape measure doesn't have opinions.

Why naming him works

Giving the scales a daft name isn't only a joke. Therapists use a similar idea called externalising: you treat a problem as something outside you, with its own name, rather than something you are.⁴ The number becomes the Doctor's opinion. Not your worth.

All 18 chapters of Basic Training