Why your weight goes up and down every day
Short answer: Day-to-day changes are mostly water, not fat. Salt, carbs, food still in your gut, hydration, sleep, exercise and hormones can move the scale by 1 to 2 kg (2 to 4 lb) overnight. To see real progress, look at a 7-day average instead of a single weigh-in.
What moves the scale overnight
- Salt: a salty dinner makes your body hold extra water for a day or two.
- Carbs: stored carbohydrate is kept with water, so a high-carb day can add weight that is not fat.
- Food and drink still in you: a late or large meal is simply weight you are carrying.
- Hard training: sore muscles hold water while they recover.
- Time of day and clothes: an evening weigh-in is usually heavier than a morning one.
Why a 7-day average works
Averaging the last seven weigh-ins cancels out the random ups and downs. If the average line slopes down over two or three weeks, you are losing weight, even if today's number is higher than yesterday's.
How to read your chart
- Compare this week's average with last week's, not today with yesterday.
- Look at a month or more before deciding something is not working.
- Missing days are fine. The average still works with gaps.
In Weighjot
Every chart shows a 7-day average line on top of your daily weights, with 1W, 1M, 3M, 1Y and All views. After each weigh-in, a result card shows your 7-day average and 30-day change.