In the first 30 days of tracking, expect the scale to move for the wrong reasons in week one, the trend line and the expenditure estimate to settle in weeks two and three, and the first adjustment that actually means something around week four. That is the shape MacroDiet's onboarding describes — log daily; the estimate updates on day 3; your first check-in arrives next Monday; by 30 days the plan is aligned — and it is also what the arithmetic of a 7-day-half-life trend predicts. Here is the month, week by week.
Week one — noise
Two things happen in week one, and neither is fat or muscle.
First, your intake changes, so your water changes. Less carbohydrate means less stored glycogen and less water bound to it; less salt means less retained water; more attention to food often means smaller gut contents. Each of those shows on the scale within days. A drop of a kilogram or more in the first week is common and is mostly this. It is real mass, it is not stored energy, and it will not repeat next week.
Second, the trend line has almost no history. The smoothing seeds itself with your first reading and moves 9.4% of the way toward each new one, so after seven daily readings the line is still more than half made of its first day. It is doing exactly what it should — refusing to chase the water shift — which means it will look slower than the scale. That is correct, not a lag to worry about.
Meanwhile the app's expenditure estimate is a formula: Mifflin-St Jeor times an activity multiplier, which by its own in-app note may be higher or lower than your true expenditure — typically by 100–200 kcal, sometimes a few hundred. After three consecutive logged days it starts updating from your data.
| Day | What the app does | What you see |
|---|---|---|
| 1–2 | Stores food logs and weigh-ins; estimate is still the formula | Scale moving with water; trend ≈ first reading |
| 3 | First data-driven expenditure update | A small change in the estimate, up or down |
| 4–7 | Keeps updating while 3 food days + 1 weigh-in per 7 are met | Scale noisy; trend beginning to bend |
| First Monday | First check-in | A small, hedged adjustment (see week four) |
In plain terms: week one is a calibration week for you and for the app. Log everything; conclude nothing.
Weeks two and three — the estimate settles
By the end of week two the trend has absorbed three-quarters of any change that began on day one; by the end of week three, seven-eighths. This is the half-life arithmetic:
after 7 days: 50% · after 14 days: 75% · after 21 days: 87.5%
So the trend value at day 21 minus the trend value at day 0 is a fair estimate of what actually happened, minus the water. The scale, by contrast, has spent these two weeks wandering around its new level, and comparing any single morning with any other single morning still tells you little.
The expenditure estimate is doing the same settling. It compares logged intake with the movement of the trend, and with two to three weeks of both it typically has a good fix on the number. During this ramp it is allowed to move in larger steps, which can overshoot and come back by a few tens of kcal before it steadies; that is the estimate finding its level, not your body changing week to week. Keeping the minimums — three logged food days and one weigh-in in every 7-day window, daily if you can — is what lets it converge. Miss the weight floor and it pauses ("holding") until the next weigh-in.
Two habits carry the most value in these weeks. Weigh in under the same conditions every morning (how to weigh yourself), and log food on ordinary days as carefully as on good ones, because the estimate is only as honest as the intake it is compared against.
Week four — the first real adjustment
Check-ins arrive weekly from the first Monday, but the one at the end of the first month is the first whose inputs are mostly signal. It is also the point at which the app's own tutorial says the estimate is refined: after 20–30 days of consistent tracking.
Adjustments before then are deliberately hedged. The reasoning is simple: a one- or two-week deviation between the planned rate and the trend is more likely to be water than a true change in expenditure, so the update moves a fraction of what naive week-over-week arithmetic would say, and moves further only if the trend holds into the following weeks. Concretely, if the raw maths after a two-week stall says "cut 500 kcal", an early check-in is designed to move a couple of hundred, and to move the rest only if weeks three and four agree. That is why the first adjustments feel small: they are meant to.
What to look at when the week-four check-in lands:
| Question | Where the answer is | What it means |
|---|---|---|
| Did the trend move as planned? | Trend at day 28 vs day 0, against the planned weekly rate | A real 4-week number; the water shift is out of it |
| Did the estimate settle? | Expenditure line over the last two weeks | Small wobbles are fine; a line still swinging by hundreds means the minimums were not met |
| Is the adjustment reasonable? | The check-in's new target vs the old one | Expect tens to a couple of hundred kcal, not a reset |
| Did anything else change? | A waist or limb girth vs day 0 | The composition check the scale cannot do |
From here the pattern repeats: a week of new data, a hedged update, a trend that is trustworthy over any three-week span. The calorie deficit calculator shows the rate arithmetic the check-in is working toward; the trend line shows whether reality is keeping up. Neither is a verdict on a week.
The short version
Week one moves the scale with water and teaches the trend nothing; log everything and conclude nothing. Weeks two and three let the 7-day-half-life trend absorb 75–87% of any real change and give the expenditure estimate the two to three weeks it needs to settle — provided three food days and one weigh-in land in every 7. Week four brings the first check-in whose adjustment is mostly signal, and it will be smaller than the raw arithmetic because early updates are hedged on purpose. From day 30, a three-week trend slope means what it looks like. Nutrition and training decisions follow that slope, not the first week's scale. Educational overview only — not medical advice.