Of course, your weight varies throughout the day. Your weight is different morning/evening, before/after eating, and so on. Naturally if you are tracking your weight, you should measure your weight at exactly the same time each day.

However, as a curiosity, I have found variations as high as 2 or even more kilograms! (Call it 2% to 3%.)

Does anyone have any specific information on the normal or usual weight variation through the 24 hours of day? Is "two or three kilograms" just wildly too much??

I realise that "extreme weight managers" such as you amazing boxers, bodybuilders and so on can deliberately vary your weight by huge amounts in a day or less. However what I am asking about here is the normal variation for a typical person, eating and drinking normally, perhaps doing an hour of aerobic exercise a day.

Anyway - in normal life is a weight variation as high as 2-3 kg per day, unusual? What's the norm? Thanks!

By the way: as an engineer, in our house we know that most bathroom scales, both electronic and spring, are hopeless (variation of three or even more kilograms either way). In fact, as a project we bought quite a few scales and tested them - as expected they are all hopeless. I think the ONLY half-decent consumer scale is the:

Soehnle 'centerpoint-alpha' model.

It's not much more expensive than other (comic) electric scales. Ideally, purchase a mechanical "beam balance" (like you see in the doctor's office). Otherwise, I think there's only that model mentioned, worth buying.

One problem is that model, must be treated with some respect, it's a precision instrument (it's a difficult job to weigh something as heavy as the human body). It is probably advisable to leave it in one spot. If you have to move it daily (eg, in to a cupboard) it's probably not a good idea - or use extreme care. I wouldn't be surprised to see it damaged in shipping. And it needs a very hard, very flat floor. Commercial scales that can weigh 100kg+ are pretty delicate and need a lot of set-up, levelling and so on. It's tough. I hope this multi-unit test helps someone in the future!!!