In week six the scale shows 0.4 lb (0.2 kg) less than seven days ago. A colleague on the same medication lost 3.3 lb (1.5 kg) in the same stretch. You wonder whether something is off with you.
There is no single normal curve, only a range. In the STEP 1 trial, body weight on semaglutide 2.4 mg fell by an average of 14.9 percent at week 68, against 2.4 percent on placebo. An average describes no individual person. Your curve has steps, flat weeks and outliers, and you only see its shape in the trend weight.
What an average over 68 weeks tells you
Apply the trial figure to a person at 220 lb (100 kg): on average that is 33 lb (14.9 kg) lost, leaving 188 lb (85.1 kg) after 68 weeks. The placebo group lost 5 lb (2.4 kg) on average. Per week that is 0.5 lb (0.22 kg), or 0.22 percent of the starting weight. At 176 lb (80 kg) the same 14.9 percent is about 26 lb (11.9 kg), at 265 lb (120 kg) about 39 lb (17.9 kg). The percentage scales with your starting weight, the pounds do not.
That average sits below the usual rule of thumb of 0.5 to 1 percent per week, which How fast should you lose weight? explains. It does not mean every week brings 0.5 lb. One week with 1.3 lb (0.6 kg) and three weeks without any loss give the same mean as four weeks of 0.33 lb (0.15 kg) each. Both paths are possible, and only the trend over several weeks tells either one apart from a real stall.
Why the curve has steps
Your doctor changes the dose in steps. After a change, the weekly rate can move up or down. The useful question is therefore not how much you lost in week six, but how fast your trend runs on the current step.
Ordinary fluctuation comes on top. Water, salt, digestion and meal timing shift the daily value by several hundred grams, also on a therapy. Why your weight fluctuates every day covers the causes. Take daily values of 210.3 lb, 208.5 lb, 209.9 lb, 208.8 lb and 209.4 lb (95.4, 94.6, 95.2, 94.7 and 95.0 kg). They look like ups and downs. The trend behind them sits near 209.4 lb (95.0 kg) and can read 208.6 lb (94.6 kg) a week later, without any single daily value showing it. Two flat weeks of daily values are no stall as long as the trend moves. A plateau exists once the rate stays below 0.1 kg (0.2 lb) per week for several days. With Pro, Trendcurve flags that in the "Patterns" card.
How to read the curve in Trendcurve
The trend weight smooths the daily values, as Trend weight instead of the daily value describes. Trendcurve calculates the weekly rate from the last 14 trend values, so it jumps around far less than the difference between two weigh-ins.
Under "Settings & more → Medication tracking" you switch the feature on, enter dose and injection day, and get a weekly reminder that you tick off with "Done". Every dose change creates a marker in your history. That part is free. The "Dose steps" card in the Analysis tab is Pro: for each step it shows period, duration, trend change and weekly rate, and it draws the steps as bands behind the chart.
An invented example, not an expectation:
| Step | Duration | Trend change | Weekly rate |
|---|---|---|---|
| 1 | 4 weeks | minus 0.8 kg (1.8 lb) | 0.2 kg (0.4 lb) |
| 2 | 4 weeks | minus 1.6 kg (3.5 lb) | 0.4 kg (0.9 lb) |
| 3 | 6 weeks | minus 1.8 kg (4.0 lb) | 0.3 kg (0.7 lb) |
| 4 | 4 weeks | minus 0.4 kg (0.9 lb) | 0.1 kg (0.2 lb) |
Step 4 looks weak. At 0.1 kg per week it still sits on the plateau threshold, not below it, and four weeks is a short time. Before you conclude anything, check whether the trend falls again on the next step. Name and dose stay on your device.
Trendcurve also warns when your measured rate exceeds 1 percent of body weight per week. At 220 lb (100 kg) that is more than 2.2 lb (1 kg). A warning like that is a reason to talk to your doctor, not to adjust the dose yourself.
What the scale does not show
Weight is more than fat. In a pooled analysis of 40 studies, lean mass made up 29.1 percent of the weight lost on GLP-1 based agents on average. With 33 lb (15 kg) lost, that would be roughly 10 lb (4.4 kg) that did not come from fat. An individual can land above or below that.
The trend cannot separate fat from lean mass. With Pro, body measurements, meaning waist and body fat from Apple Health, and progress photos add to the picture. If your waist shrinks more slowly than your weight, or you feel weaker, bring it to your next appointment. Trendcurve is not a medical device and gives no advice on dose or intake.
Four questions for your curve
- Does the trend fall on the current step, even slowly? Then the step works, and the daily values are noise.
- How long has the step been running? One week of data is not enough, because the weekly rate needs 14 trend values.
- Is the rate above 1 percent of body weight per week? Then talk to your doctor.
- Do weight and body feel agree? Strength, waist and clothes tell you something the scale does not know.
Changes, breaks and what follows
A dose change, a break or a switch can be saved as an experiment or marker. In the evaluation (Pro), Trendcurve compares the weekly rate of the 28 days before with the run itself and with the stretch afterwards. Each section needs at least 7 days and 4 weigh-in days. The card carries the fixed note "Correlation, not cause": it shows what changed in the trend, not why.
Enter every dose change on the day it starts, so the curve can later explain why it bends there. Weigh yourself at the same time of day, and judge a step only once your trend has two weeks of data on it.