Plateaus are the statistical norm, not the exception
A stall lasting two to four weeks is a normal part of most weight-loss journeys, not evidence that something has gone wrong. Multiple physiological factors converge to produce them.
The usual suspects
Three mechanisms most often explain a plateau: your TDEE has genuinely dropped as you've gotten lighter (so your old deficit has shrunk or disappeared), water retention is temporarily masking real fat loss, or your adherence has quietly slipped without you fully registering it.
How to tell which one you're dealing with
If the scale has stalled but measurements, photos, or how clothes fit are still improving, water retention is the likely culprit. If nothing is moving on any metric, recalculating your calorie target at your current (lower) weight is usually the first step, since your deficit may have narrowed without you changing anything.
When plateaus typically break
Plateaus driven by water retention often resolve within a week or two on their own. Plateaus driven by a shrunken deficit generally require either a lower calorie target, an increase in activity, or a planned maintenance break to reset hunger hormones before resuming.