Why glucose matters
Insulin resistance builds for years before a blood test catches it. These guides explain what is happening, what a sensor can and cannot show you about it, and where the evidence runs out. Every claim states how strong the evidence behind it is and cites the paper it came from.
Written from the research, not around anyone's thesis. Researchers appear in the reference lists and nowhere else, and where the field genuinely disagrees we say so instead of picking a side.
How to read the evidence labels
Every claim on this page carries a label saying how much weight it can hold. The label describes the strength of the finding, not the prestige of the journal it appeared in.
- Strong evidenceA large randomised trial, a long cohort study, or agreement between several of them.
- Emerging evidenceReal, but thin — small, short, observational, or not yet replicated.
- ContestedCompetent researchers actively disagree. We are not picking a side for you.
Guides
- What insulin resistance is, and why it starts before diabetes
Insulin resistance is your cells responding poorly to insulin, so your body makes more of it. Blood glucose can stay normal for years while this happens — which is exactly why it goes unnoticed.
3 × Strong evidenceUpdated 2026-08-07
- Glucose versus insulin: what a CGM does not show you
A continuous glucose monitor measures glucose in the fluid between your cells. It does not measure insulin. That gap decides what a normal-looking week can and cannot tell you.
2 × Strong evidenceUpdated 2026-08-07
- How to read your own glucose curve
Peaks, area under the curve, and the overnight baseline each tell you something different. Here is what a trace can support, and where people routinely over-read it.
3 × Emerging evidenceUpdated 2026-08-07
- What the evidence actually supports for people without diabetes
The honest summary: strong evidence in diabetes, reasonable grounds in prediabetes, and thin evidence that a sensor improves health in people who are already metabolically healthy.
5 × Strong evidence2 × Emerging evidenceUpdated 2026-08-07
- Time in range, and why it beats a single number
Time in range is the share of the day your glucose sits between 3.9 and 10.0 mmol/L. It carries information that an average cannot, and it has been validated against real complications.
4 × Strong evidenceUpdated 2026-08-07
- CGM accuracy: what MARD means, and what it hides
MARD is the average gap between a sensor and a laboratory blood test. It is the standard accuracy figure, it is genuinely useful, and it is routinely compared between studies that cannot be compared.
1 × Strong evidence1 × Emerging evidenceUpdated 2026-08-07
- Food, movement, sleep and stress: what actually moves the curve
Four inputs change what a sensor shows you. The evidence behind them is not equally strong, and the one with the best evidence is the one people expect least.
1 × Strong evidence5 × Emerging evidenceUpdated 2026-08-07
- Prediabetes: the window where a sensor earns its keep
Prediabetes is the stage where the numbers have moved but the outcome is not settled. Roughly as many people return to normal as progress — and what decides it is well established.
5 × Strong evidenceUpdated 2026-08-07
- Who should not bother with a CGM, and what to do instead
Some readers will get nothing from a glucose sensor that a cheaper test would not give them. Some need a different device from the one they are about to buy. Both are worth saying plainly.
3 × Strong evidence2 × Emerging evidence1 × ContestedUpdated 2026-08-07