Why your weight goes up and down every day
Gaining a kilo overnight is almost never fat. Day-to-day changes mostly come from water and what's in your system. Here's what moves the scale, and how to read it.
- Swings of 1–2 kg in a day are common.
- Weigh at the same time each day.
- Follow the trend, not the reading.
What moves the scale day to day
Several things change your weight without changing body fat:
- Salt: a salty meal makes your body hold extra water for a day or two.
- Carbohydrates: stored carbohydrate is held with water, so a carb-heavy day adds weight.
- Food and drink still in your system, and when you last went to the toilet.
- Hormonal cycles, which can cause water retention for several days.
- A hard workout, which can cause temporary water retention in muscles.
How to weigh yourself consistently
Same scale, same time (ideally in the morning after the toilet and before eating), similar clothing. Consistency makes the readings comparable, even though they'll still vary.
Follow the trend
Averaging several days smooths out the noise. HYFO shows a weighted 7-day trend as the headline and your daily weigh-ins as dots, so a heavy morning doesn't hide real progress.
Questions
How much can weight fluctuate in a day?
Swings of 1–2 kg are common, mostly from water and food. If you notice sudden, lasting changes or swelling, talk to a doctor.
Try HYFO
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