Our Methodology
Truth Nutrition publishes its quality criteria openly so that anyone can scrutinise and verify our editorial standards. Every study that appears on this platform has passed all of the criteria below. Where a study fails even one criterion, it is not included — regardless of its conclusions.
Research quality criteria
Sample size
Randomised controlled trials must include a minimum of 500 participants. Observational and cohort studies must include a minimum of 1,000 participants. Population-level claims about chronic disease risk require studies of 10,000 or more participants.
Study duration
Studies examining metabolic or physiological outcomes (e.g. blood glucose, cholesterol) must run for at least 12 weeks. Studies examining chronic disease risk outcomes must run for at least 2 years. Studies making claims about cancer or cardiovascular disease are only included if based on long-term cohort data of 5 years or more.
Peer-reviewed publication
All included research must be published in a peer-reviewed journal. Pre-print studies, industry white papers, and non-peer-reviewed reports are excluded.
Funding transparency
The funding source of every study is assessed before inclusion. Studies with undisclosed funding are excluded. Studies with declared industry funding are either excluded or flagged prominently with an industry conflict warning — never included without disclosure.
Study design
Randomised controlled trials and systematic reviews or meta-analyses of cohort studies carry the most weight. Single observational studies are included only when very large (10,000+ participants) and when their findings are consistent with the broader literature on that topic.
Evidence grading system
Each topic is assigned an evidence confidence rating. This reflects the quality and consistency of the studies available, not simply whether the finding is positive or negative.
Multiple large, independent, long-term studies — typically including systematic reviews or meta-analyses — reaching consistent conclusions across different populations and study designs.
Good quality studies exist but with limitations: smaller samples, shorter durations, fewer replications, or some conflicting findings in the literature. The direction of evidence is broadly consistent.
Early-stage research that meets our quality criteria and warrants attention, but where the body of evidence is not yet sufficient to draw firm conclusions. These topics are included because the research is rigorous, not because the findings are settled.
What we do not include
- Studies with undisclosed funding sources
- Studies with sample sizes below our thresholds
- Studies running for insufficient duration to observe the relevant outcome
- Research not published in peer-reviewed journals
- Studies whose methodology has been publicly challenged and not replicated
- Any content produced or commissioned by food, supplement, or beverage manufacturers
A note on uncertainty
Nutrition science is genuinely complex. Unlike pharmaceutical trials, it is not possible to blind participants to their diet for years at a time. Where the evidence is mixed, contested, or genuinely uncertain, we say so — clearly and explicitly. We do not present uncertain findings as settled fact. Honest uncertainty is more useful than false confidence, and it is what separates Truth Nutrition from the sources of misinformation we are designed to counter.