Weight-Loss Rate Checker
You know how much you’ve lost. This tells you the two things the scale doesn’t: how fast that actually is as a share of your body, and roughly how much of it was lean mass — which is the number resistance training changes.
Your rate so far
Your pace
0.91% of body weight / week
about 2 lb/week — clinical guidance has long described roughly 1–2 lb a week as a sensible pace, and an athlete study found 0.7%/week gentler on lean mass than 1.4%
Lean mass in the loss so far
4.2–6.2 lb
pooled trial data puts lean mass at ~26% of weight lost with lifestyle change alone — and ~17.5% when resistance training is added. The training changes the composition of the loss.
What we deliberately won’t tell you: whether your pace is right. On a GLP-1 the rate is substantially set by the medication and your response to it, and judging it is your healthcare provider’s job, not a calculator’s. What the research does say clearly is that whatever the pace, protein and resistance training shift what the loss is made of.
Rough estimates for orientation, not a prediction, a target, or medical advice. Lean-mass shares are pooled trial averages — individual results vary widely, and lean mass includes water, not just muscle. Questions about your own pace belong with your healthcare provider.
The number worth knowing by heart
Across pooled randomised trials, lean mass made up about 26% of the weight people lost through lifestyle change alone — and about 17.5% when resistance training was part of the programme. Same weight loss, different composition. That gap is the entire argument of this site, in one comparison.
Rate matters too, though less cleanly than the internet suggests. In athletes who were strength training, losing 0.7% of body weight a week was gentler on lean mass than 1.4% — but on a GLP-1 your rate is substantially set by the medication, which is why this tool reports your pace without grading it. If your rate concerns you, that’s a conversation with your healthcare provider, who can actually adjust something.
You can’t choose your rate on a GLP-1 — but the 26%-versus-17.5% gap is entirely yours to choose. Mira is the resistance-training half: short, form-scored sessions through your phone, built around your energy and your week.
Build my plan