68 guides · 9 topics
Health guides with the evidence graded
Every guide on this site does three things most health writing skips: it gives the direct answer in the first paragraph, it grades how strong the evidence behind that answer actually is, and it says plainly where reading stops being useful and a clinician starts.
Our 68 guides, by evidence grade
Consistent human trials or a major guideline stand behind the central claim.
The direction is well supported; the size of the effect is less certain.
A plausible mechanism, with thin or mixed human evidence. Hold it loosely.
Credible researchers disagree right now. The guide sets out both sides.
Got a result back? Look up the number
One test or marker per guide: what it measures, the reference range, and what can move it.
Browse by topic
All 68 guides →Metabolic health12 guides
Blood sugar, insulin resistance, prediabetes and visceral fat: what the tests show and where the thresholds sit.
Understanding your bloodwork10 guides
One lab marker per guide: what it measures, the reference range, and what can push a result outside it.
Micronutrients9 guides
Vitamins and minerals: intake guidelines, deficiency signs, timing, and how nutrients compete with each other.
Heart & circulation8 guides
Blood pressure, cholesterol, resting heart rate and fitness markers, read against current guidelines.
Sleep7 guides
How much sleep adults need, what the stages are, and how far a sleep tracker can be trusted.
Gut health7 guides
Fibre, the microbiome, bloating, and the tests that separate everyday symptoms from something more.
Stress & inflammation6 guides
Cortisol, inflammation markers, and the claims made about bringing them down.
Screening & prevention3 guides
Which checks are recommended at which age, and how to prepare so the result means something.
Tools6 guides
The apps people use to track food and health, judged on whether their numbers have been checked.
Latest guides
RSS feed →Tools
How Accurate Is Cal AI?
The most heavily marketed AI calorie app is also the only major one whose accuracy figure exists purely as marketing — no published methodology, no disclosed test set, and a methodology note explaining why an independent research group could not evaluate it at all.
Limited evidence2 Nov 2026
Tools
How Accurate Is Cronometer? (And What's Actually Free)
The best micronutrient database in consumer tracking, a solid mid-pack accuracy figure — and a paywall sitting exactly where the modern logging features live. What the weighed-food data says, and what Gold buys.
Moderate evidence2 Nov 2026
Tools
How Accurate Is Lose It!?
The friendliest first week in calorie tracking, the second-highest error ever measured on the same weighed plates — an honest look at what simplicity costs in the arithmetic, and when that trade is the right one.
Moderate evidence2 Nov 2026
Tools
How Accurate Is MacroFactor?
The best adaptive-coaching idea in the category, a solid mid-pack measured figure with a catch — the portion is yours to supply. And there is no free tier at all. What the weighed-food data says about the app lifters swear by.
Moderate evidence2 Nov 2026
Tools
The Best Calorie Tracking Apps, Graded by Evidence (2026)
Almost every calorie app publishes an accuracy figure, and almost every one of those figures was produced by the company selling the app. This ranking is built on one question instead: did anyone outside the company check?
Moderate evidence1 Nov 2026
Tools
How Accurate Is MyFitnessPal?
The biggest food database in consumer tracking is also the least-accurate calorie figure ever measured against weighed food — 11.2% error in the one head-to-head test that used a scale. Here is what that number means, why it happens, and what to do about it.
Moderate evidence1 Nov 2026