The research behind Metabolicum's evidence-based approach
Not all research is equal. We assign confidence grades to each source based on study design, sample size, replication status, and methodology. This helps you understand how confident you can be in each finding.
High Confidence
Replicated findings across multiple well-designed studies
Good Confidence
Well-designed single studies with strong methodology
Moderate Confidence
Observational data with consistent patterns
Emerging Evidence
Mechanistic or theoretical - interpret cautiously
Clinical Consensus
Practitioner experience without formal trials
Why are we so careful about evidence grading? Because a significant portion of published research fails to replicate.
| Study | Finding | Grade |
|---|---|---|
| Begley & Ellis, 2012 | Only 21% of landmark cancer studies could be replicated | A |
| Open Science Collaboration, 2015 | Only 36% of psychology studies replicated | A |
| Ioannidis, 2005 | Theoretical framework explaining why most findings are false | A |
This doesn't mean you should distrust all research. It means:
We grade evidence honestly so you can calibrate your confidence appropriately.
In-depth analysis of foundational studies with translated summaries
Showing 5 studies
Grundy SM, et al. • Circulation • 2004
Metabolic syndrome diagnosed when 3 of 5 criteria present: waist >102cm(M)/88cm(F), TG ≥150, HDL <40(M)/50(F), BP ≥130/85, fasting glucose ≥100 mg/dL.
NCEP ATP III • JAMA • 2001
ATP III criteria: presence of ≥3 of abdominal obesity (waist >102/88 cm), elevated TG (≥150), low HDL (<40/50), elevated BP (≥130/85), elevated fasting glucose (≥110, later revised to ≥100).
Alberti KG, et al. • Circulation • 2009
Harmonized criteria: 3 of 5 required with unified thresholds - TG ≥150, HDL <40(M)/50(F), BP ≥130/85, fasting glucose ≥100. Waist circumference uses population-specific cutoffs.
Reaven GM • Diabetes • 1988
Insulin resistance is present in ~25% of nonobese individuals with normal glucose tolerance. The compensatory hyperinsulinemia drives hypertension and dyslipidemia, creating a high-CVD-risk phenotype.
Gami AS, et al. • Journal of the American College of Cardiology • 2007
Metabolic syndrome was associated with approximately 2-fold increased risk of cardiovascular events (RR ~2.0) and 1.5-fold increased risk of all-cause mortality across studies.
Primary thresholds come from Grade A sources. When Grade A evidence suggests a range rather than a single value, we present the range with context.
We draw on Grades A-C for educational claims, clearly labeling evidence quality. Grade D and E content is marked as theoretical or practitioner-derived.
This bibliography contains the research supporting Metabolicum's evidence-based approach.
Last comprehensive review: December 2025