The old rule of thumb falls short
A common claim: about 2 MJ less a day, roughly 480 kcal, means a steady 0.5 kg less per week. According to Hall and colleagues, this is wrong. The rule ignores that expenditure changes with body weight.[1]
Weight responds slowly
In Hall's model, half of a weight change is reached after about 1 year and 95% after about 3 years. People with more body fat take longer to reach a new balance.[1]
This applies to an average adult with overweight and to a change that lasts.[1] For one person, it is not a prediction.
Single days say little
An analysis of 4,657 measurements from 80 adults found a weekly rhythm: weight was higher on Sunday and Monday and fell during the week. The authors consider such changes normal.[2]
What the app shows instead
The app shows what you entered and, for weight, a mean value if you want one. It names no date and no kilos you will reach.
The app does not replace medical advice.