Weight loss usually stalls for one of four reasons, and the most common is the least dramatic: your expenditure fell with your weight while your target stayed where it was. The others are logging that has quietly drifted, water weight hiding a trend that is still falling, and a target that was never recalculated. This page takes them in that order, with the numbers, and ends with what to recompute and when.
A weight-loss plateau is arithmetic before it is anything else. Nothing here is a health claim about your metabolism; it is what the energy-balance equation and the calculator's own formula predict.
Your expenditure fell with you
Every part of daily expenditure scales with body size to some degree, and the calculator's own BMR formula makes that explicit: Mifflin-St Jeor carries 10 kcal per kilogram of body weight. Lose 10 kg and the formula BMR drops 100 kcal; multiply by the activity factor and the TDEE drops more.
Worked example — male, 180 cm, 35 years, trains 4–6 times a week, moderate day-to-day activity:
| At 90 kg | At 80 kg | Change | |
|---|---|---|---|
| BMR (Mifflin-St Jeor) | 1,855 kcal | 1,755 kcal | −100 kcal |
| TDEE (× 1.55) | 2,875 kcal | 2,720 kcal | −155 kcal |
| Moderate rate (0.5%) weekly loss | 0.45 kg | 0.40 kg | −0.05 kg |
| Deficit the rate asks for | 495 kcal | 440 kcal | −55 kcal |
| Calorie target | 2,380 kcal | 2,280 kcal | −100 kcal |
Now suppose this person is still eating the 2,380 kcal target computed at 90 kg. At 80 kg the real deficit is 2,720 − 2,380 = 340 kcal, not 440. That is 0.31 kg a week instead of 0.40 — a quarter slower from the formula alone. On top of the formula, actual expenditure tends to fall a bit further than body size predicts during a diet (less spontaneous movement, cheaper movement in a lighter body). This is routine and expected, not a fault.
In plain terms: the plan was written for a heavier person. You are not that person any more.
Logging drift
The second cause leaves no fingerprints in the log, which is what makes it hard to spot. Nobody logs a 3,000 kcal day by mistake. What happens instead is that oil goes back to a pour instead of a weigh, a sauce stops being logged, the "medium" banana gets larger, the weekend tracking gets rougher. Each item is small; the sum is not.
A useful test is two weeks of deliberately strict logging — weigh everything, log every calorie-bearing item, estimate the untrackable meals generously — while changing nothing else. If the trend starts moving again, the deficit was never gone; it had leaked. How accurately do you need to track? covers which errors matter and which do not, including why a single half-logged day distorts an expenditure estimate for weeks.
Water weight masking the trend
The third cause is not a stall at all. Scale weight carries a few kilograms of noise — water, glycogen and its water, sodium, gut contents — that can move by more than a week's expected fat loss in either direction. A hard training week, a salty meal, a higher-carb day, or the menstrual cycle can hold scale weight flat for one or two weeks while the trend underneath keeps falling.
The trend weight exists to see through this. MacroDiet smooths weigh-ins with an exponential moving average that has a 7-day half-life, so a single day's swing moves the trend by under a tenth of its size — the overnight-gain page does the arithmetic. MacroDiet's own Weight Trend screen puts it this way: "if day-to-day fluctuations stress you out, follow the trend." Its estimated caloric deficit card reads the rate of change over the past three weeks for the same reason.
The practical rule: a flat *scale* for one to two weeks is noise until proven otherwise; a flat *trend line* for three to four weeks is a real signal.
What to recalculate, and when
| Signal | Likely cause | What to do |
|---|---|---|
| Scale flat 1–2 weeks, trend still falling | Water masking the trend | Nothing; keep logging and weighing |
| Trend flat 3–4 weeks, logging honest | Expenditure fell; target stale | Re-run the calculator at current weight |
| Trend flat, logging got looser | Logging drift | Two strict weeks, then reassess |
| Trend flat, target already at the floor | Deficit being cut short by the floor | Rate is not the lever — see the floors page |
Recalculating is not a cut so much as a correction. Re-running the calorie deficit calculator at 80 kg instead of 90 produces the 2,280 kcal target above on its own; the percentage rate has already shrunk the deficit to match the lighter body. If the new target is at or near the calorie floor (1,500 kcal male / 1,200 kcal female on the standard setting), the deficit has run out of room, and the floors page explains what that means. If you have been dieting for a long stretch, a planned week or two at maintenance — see diet breaks — is another honest option, and the trend will tell you what it did.
Two weeks is the right cadence for checking; three to four weeks of trend is the right window for deciding.
The short version
A stall is usually a deficit that shrank without you noticing. Expenditure falls with weight (about 155 kcal a day from 90 to 80 kg in the example), logging drifts, and water hides the trend for a week or two. Read the trend weight, not the scale; if the trend has been flat for three to four weeks with honest logging, re-run the calculator at your current weight and let the percentage rate set the new number.
Educational overview only — not medical advice. Zyra is a training and nutrition tracking tool; the rates, caps and floors on this page describe how the calculator behaves, not what any individual should do.