Metabolic Fitness Index — Open, Transparent Score
A transparent 0–100 metabolic score from your CGM metrics, waist-to-height and resting heart rate — full formula and weights shown.
- Recovery
- 2 cited sources
- Runs in your browser
Your Metabolic Fitness Index
60 / 100
| Input | Score | Weight |
|---|---|---|
| Time in rangeT2 · moderate evidence | 63 | 30% |
| Glucose stabilityT2 · moderate evidence | 52 | 20% |
| Average glucose (GMI)T2 · moderate evidence | 60 | 20% |
| Waist-to-heightT1 · strong evidence | 57 | 15% |
| Resting heart rateT2 · moderate evidence | 70 | 15% |
What this is
A transparent self-tracking score that summarises five metabolic markers into one number, with every weight and mapping published. Best used to watch your own trend over time.
What this isn’t
A diagnosis, a medical test, or a validated predictor of disease. It cannot tell you whether you have a metabolic condition — that is for a clinician and proper testing.
Transparent composite index v1.0.0. It is not a medical test and has not been validated against health outcomes. The full formula, weights and evidence tiers are shown above and in the methodology below.
Methodology
The Metabolic Fitness Index is an open composite index (v1.0.0). Unlike the scores buried inside proprietary wearables, everything about it is published: the inputs, the sub-score mappings, the weights, and the evidence tier of each input. You — or anyone — can reconstruct the number exactly.
Each input is mapped to a 0–100 sub-score (higher = more favourable) using a clamped linear scale between documented anchor points, then combined as a weighted average:
| Input | Weight | Tier | Sub-score anchors (0 → 100) |
|---|---|---|---|
| Time in range | 30% | T2 | 50% → 90% |
| Glucose stability (%CV) | 20% | T2 | 45% → 20% |
| Average glucose (GMI) | 20% | T2 | 7.5% → 5.0% |
| Waist-to-height | 15% | T1 | 0.60 → 0.40 |
| Resting heart rate | 15% | T2 | 90 → 50 bpm |
The anchor points come from recognised references — the international CGM consensus (time in range ≥70%, %CV < 36%), ADA A1C bands for GMI, the 0.5 waist-to-height boundary, and typical adult-to-athletic resting heart rates. They are self-tracking anchors, not diagnostic thresholds. Full detail on the house methodology — normalisation, weighting, versioning — is on the index methodology page.
If you leave an input blank, the index renormalises across what you provided and flags reduced confidence, rather than guessing a value.
Interpreting your result
Read the breakdown, not just the headline. The radar and table show which markers are pulling your score up or down — that's where the useful information is. A single number is only a summary; the point of publishing the sub-scores is so you can see what to work on, framed as a modifiable lever rather than a verdict.
Track your own trend over weeks and months. Because the weights and mappings are fixed and versioned, a change in your score reflects a real change in your inputs, not a moving goalpost.
Limitations
- This is a transparent self-tracking construct, not a medical test, and it has not been validated against health outcomes.
- The sub-score anchors are reasonable but chosen by us; different anchors would give different numbers. They are published so you can judge them.
- CGM-derived inputs inherit CGM's limitations, and for people without diabetes the value of optimising glucose metrics is uncertain (see the CGM metrics tool).
- Any concern about your metabolic health belongs with a clinician and proper testing, not a self-tracking score.
Sources
Pull the receipts — 2 cited sources
Frequently asked questions
- What is the Metabolic Fitness Index?
- It's an open, transparent composite score (0–100) that combines five self-tracking metabolic markers into one number, with the full formula, weights and evidence tiers shown on the page. Unlike the scores inside proprietary wearables, nothing is hidden — you can reconstruct exactly how it was calculated.
- Where do I get the inputs?
- Time in range, glucose variability (%CV) and GMI come from a CGM — our CGM metrics calculator computes them from your readings. Waist and height you can measure with a tape; resting heart rate from a morning pulse or a wearable.
- Is a high score good?
- Higher is more favourable by the index's design. But it is a self-tracking construct, not a medical test — it has not been validated against health outcomes, and it can't diagnose anything. Use it to track your own trend over time.
- Why these five inputs and weights?
- The weights and evidence tiers are published on the page and follow our open methodology: no single input dominates, and each is tagged by strength of evidence. Time in range, variability and average glucose carry the most weight; waist-to-height and resting heart rate round out the picture.
- Is my data private?
- Yes. Everything is computed in your browser and nothing is stored or transmitted.
Written and reviewed by Mathew Beale — MSc Biotechnology, University of Reading.
Last reviewed:
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