Since the Fitbit app became Google Health (May 2026), many users report a weight chart with a fixed, wide scale, such as 50–200 lb or 80–200 kg, so months of progress look flat. Its change figure compares two single weigh-ins. To see progress, read a 7-day trend instead. Weight Forecast shows one and a goal date; you log weight by hand.
If you weighed in daily on Fitbit and now use Google Health, you are not alone in asking why the weight line looks almost level — even when the scale and your clothes tell a different story. This guide explains what changed after the May 2026 app switch, why the chart can hide real progress, and how a 7-day trend plus an estimated goal date can help. Weight Forecast is optional and honest about limits: no Fitbit or Google Health sync, no history import — you type each weigh-in in kg or lb.
Why your Google Health weight graph looks flat
Fitbit became Google Health (May 19, 2026)
Google's help center states that starting May 19, 2026, the Fitbit app becomes the Google Health app, with automatic updates rolling out through May 26 (What is new with the redesigned Google Health app). Weight still lives on the Health tab alongside heart rate, breathing rate and SpO₂. You can export health data from app settings or your Google Account — useful if you want a backup while you also log elsewhere.
On November 2, 2026, Google's health status dashboard noted that legacy Fitbit Web API traffic was turned down (HTTP 410 Gone), which affects third-party apps that still relied on the old Fitbit connection — not the Google Health app itself, but a timely reminder that export and manual logging matter if you use more than one tool.
A fixed, wide scale squashes real change
Google's public docs do not describe the weight chart's vertical axis. In the Google Health Community, users report an unadjustable range — for example roughly ±75 lb around average weight, or about 50–200 lb (23–91 kg) and 80–200 kg (176–440 lb) on metric accounts (Community thread, July 2026). Reddit users describe the same fixed span (r/fitbit, Aug 2026).
When the axis spans tens of kilograms or a hundred pounds, a realistic loss of 2–5 kg (4–11 lb) over months can look like a nearly flat line — even though your average weight is moving.
What Google has said
In August 2026, a Google Health support reply on Reddit said the team had identified the cause of the visual issue and was working on a fix (r/fitbit discussion). Android Authority reported that version 5.07 expanded the weight graph's minimum and maximum values to make long-term change easier to see (Android Authority). Community replies after 5.07 still mention wide ranges (for example 100–300 lb). Treat those as user reports, not a guarantee of how your phone looks today — update the app and judge your own chart.
Why "this week" can say you gained weight
First weigh-in vs latest weigh-in, not averages
Users on the Community thread describe a logic change from the old Fitbit app: Google Health's change figure may use the first weight reading in the selected period minus the most recent, not the average compared to the previous period's average.
Illustrative example from user reports: if you usually weigh about 160 lb (72.5 kg) and log one heavy morning at 165 lb (75 kg) after a salty meal, the app might show +5 lb (+2.5 kg) for the week — even when most days were steady. The kg-side reports mirror the same pattern at 100 kg on an 80–200 kg axis.
Daily swings are normal
Water, salt, carbs and meal timing often move the scale 0.5–1.5 kg (1–3 lb) day to day without a matching change in body fat. That is why one morning should not override a multi-week view — compare weekly averages or a smoothed trend instead.
How to read a trend vs raw weigh-ins
Raw weigh-in vs trend line
A raw weigh-in is one noisy morning. A trend is a smoothed line through many mornings — usually a rolling average — that shows direction despite bounce. Google Health may or may not show a trend line for weight in your version; many people miss Fitbit's old running-average graph. You can still compute the idea yourself or log in a tool built around trends.
Worked example (illustrative)
Illustrative numbers only — not a user record. Seven consecutive mornings in kg (lb in parentheses):
| Day | Weight |
|---|---|
| 1 | 80.4 kg (177.2 lb) |
| 2 | 80.9 kg (178.4 lb) |
| 3 | 80.1 kg (176.6 lb) |
| 4 | 80.6 kg (177.7 lb) |
| 5 | 81.3 kg (179.2 lb) |
| 6 | 80.0 kg (176.4 lb) |
| 7 | 79.8 kg (175.9 lb) |
First vs last in that window: 80.4 → 79.8 kg = −0.6 kg (−1.3 lb). If day 5 had been your only "heavy" day at the end of the week, first-vs-last logic could have flipped to a gain. The 7-day average is about 80.4 kg (177.3 lb) — compare that to last week's average to judge direction.
Judge direction over 2–4 weeks
One good or bad week is noise. Look at whether your weekly average or 7-day trend drifts over 2–4 weeks before you change calories, training or goal targets.
Fit the axis to your data
On a chart scaled from 78–82 kg (172–181 lb), the same points above look like a real slope. That is the visual fix a wide 50–200 lb axis hides — and why many people pair Google Health with a trend-focused log.