Body composition scales

[Yikes101]

I bought some body composition scales after seeing them recommended, either on here or on a facebook group. Do people think they are really accurate? My weight fluctuates, I think it depends on what and when I ate the day before and my 💩 timings. The scales seem to think it’s my body fat and skeletal muscle that is going up and down daily. Do you think this could be true?
They’re showing me as having plenty of fat still so at least they are giving me a push to get the last bit of weight off so they were a good buy anyway!

Do you weigh every day?

I don’t find that helpful, because of course you will have drunk more/less, expelled (ahem) more or less on any given day.

I think they are accurate but you give them
a better chance if you weigh at the same time of day (I do it first thing) and once or twice a week.

They are not particularly accurate for anything other than weight. They use Bioelectrical Impedance Analysis to estimate your body composition. It sends an electrical current through your feet and legs and measures the resistance, then also uses your height, age and sex to estimate body fat and muscle. The ones that have a hand held contact are slightly more accurate as the resistance then covers your whole body and not just your lower half.

The readings will fluctuate due to your hydration levels, and generally at different times of the day depending on whether you’ve just eaten, exercised, etc etc.

I honestly wouldn’t take much notice of those readings, or any fluctuations in them.

What about getting a DEXA scan? It's approx. £150, but far more accurate.

I do weigh most days, same time in the morning before eating or drinking. I expect my weight to fluctuate and know which mornings I am likely to weigh more or less. Thanks for the explanations, that makes sense.
I’m not sure I can justify £150!

Which? recommend this one, a lot less than £150

https://www.mi.com/uk/product/xiaomi-body-composition-scale-s400/

That looks good. I'm looking it up.

This is brilliant. I bought the Hume one, and I'm ok with it. I'm sure I'm not using it to its max, and I have to subscribe but the one you showed looks bloody brilliant. Thank you

All body composition scales use your weight, height, age, and sex, then pass a small electrical current through your body. They measure how that current travels and apply a algorithm to estimate body fat, muscle mass etc based on population averages.

Some models also include hand electrodes, allowing the current to travel through both the upper and lower body but the results are still population based estimates rather than direct measurements.

Readings can be affected by hydration, recent exercise, food, time of day, temperature etc, so results can vary even when your body composition hasn't changed. Also the prediction equations based on populations have not been well validated in people experiencing the rapid body composition changes often seen with GLP1s and ongoing weight loss.

I have the Withings one. I weigh first thing each morning. I would look at a monthly average. I did a dexa and found that it was spot on 😀

They are only really useful for trends so I look at monthly averages. Building muscle happens at a snails pace even when you do everything perfectly so there is no point in noting it daily anyway.

Exactly this. Hydration changes day to day. Look up how long even 100g of muscle takes to build (3 months). I laugh when people use a BIA in the gym and claim to have gained 2kg of muscle in 4 weeks. It’s just different levels of hydration and muscle glycogen. Because of that home scales with a monthly average always better than a more expensive gym scale that’s done once a month.