: How is it possible to gain weight overnight ?



Last night I used my scale and saw that I was 92.7 Kgs. Right after that I went to bed, slept a good 8 hours without waking up and without eating or drinking anything.

This morning, I stepped back on the scale after peeing. It showed 93.2 Kgs.

How is that possible considerating I had 0 food / liquid intake between my two measurements ?

In: Biology

Scales are sometimes wrong for obscure reasons. Mine, for example, shear off 0.5 kg whenever they are next to a wall.

Measurement slop – or you changed into heavier pants.

The scale is displaying a measurement down to 0.1kg but if you really inspect the manual I’ll bet it’s actually only rated as accurate to +/- 0.5kg.

You will always lose weight overnight, exhaling carbon dioxide and water.

It clearly isn’t. Household scales are not calibrated to be precise to the gram, nor are they reliable especially after prolonged use, so you’ll always get some measurement error. If you really want to improve the precision, do a number of readings (like 5-10), weigh yourself, note the weight, repeat, then average your weight and note the discrepancy from the average (σ^2). So now you have the average variance you can use for every measurement afterwards (in both directions +/-).

As folks have mentioned, your scale is at fault.

Besides the scale just having slop, another thing to look at is the floor beneath the scale. If the floor is soft, or you move the scale between uses, or it’s on a hard floor but one that has give (ie, a flexing floorboard), those things can all influence measurements.

Or you’re a sleep eater. They exist!

Temperature and humidity can change the properties of the sensors that measure weight, and impact readings on the scale (among other things).

So if you’re taking a shower before weighting yourself, that can show you biased measurements.

I have noticed that my scale sometimes reads differently based on where I stand, or the “biased loading” as I tend to think about it. I think this is largely dependant on scale design and you might find that a higher end scale can compensate for this better. Try exact foot placement and an intentional “evening” of weight distribution. Also, padlock the fridge.