A maintenance range, and when to act
"When are two kilograms up a problem?" When they are a trend and outside a range you set before they happened. Both halves matter.
Why a range, not a number
Weight is not a number; it is a band. Water, salt, glycogen, the cycle and the gut move the scale by a kilogram or two with no fat involved — the scale page has the list — so a single maintenance weight is a target you will miss most mornings and worry about needlessly. A range absorbs the noise. The research definition of "weight maintenance" used in studies is a change of less than about three percent of body weight; the product adaptation of that is a range of roughly two kilograms either side of your maintenance weight, or about three percent for heavier or lighter bodies. Those are working figures, not a citation: the research paper defined a threshold for classifying studies, and this site borrows its scale for a personal rule.
Set it before you need it
Decide the range on the day you reach the goal, write it down, and decide at the same time what you will do when the trend leaves it. A rule made in advance is followed; a rule made in the moment is negotiated.
Reacting to a trend
The trigger is the trend — a smoothed or weekly-average weight — sitting above the range for two or three weeks. Not one reading, not one week after a holiday. Then the response is small and short: a modest deficit, a share of body weight per week at the low end of the pace calculator, until the trend is back inside. Two or three weeks, usually. What it is not is "going on a diet again": the point of catching it early is that the correction can be gentle enough to be invisible to everyone but you.
Regular self-weighing is the habit that makes this possible. A systematic review of prospective studies finds it consistently associated with better weight outcomes, in adults without eating disorders; that is an association rather than proof, and the review is explicit that "regular" varied from daily to weekly across studies. Weekly is enough for the trend.
Who this rule is not for
Anyone with a history of an eating disorder, or for whom weighing and ranges bring anxiety, restriction or a sense of failure. For those readers, a weight range is a trap, not a tool, and the right approach is one built with a clinician — and probably not built around the scale at all. This site has no advice that overrides that.
In the app
Maintenance mode keeps the trend on the progress page and re-issues the target when you ask for a small deficit; the range itself is yours to keep — the app does not nag, on purpose.