Why does the scale jump 1 kg overnight? Play with a month of weigh-ins

Your weight can move a kilo or two from one day to the next without any change in body fat. Salt, carbohydrate, fluid, food still in transit, hormones and even the weekend all show up on the scale.

Play with a 28-day simulation to see how noisy daily readings are, why a 7-day average tells you more than any single morning, and how to weigh in so the number means something.

Not medical advice: if you have a condition, take medication or have had an eating disorder, talk to a doctor first.