Olive oil's least-processed grades carry plant compounds the refined grades lose. Blood-fat and blood-vessel measures improve in controlled feeding studies, tracking those compounds rather than the fat alone. Population data link higher intake with fewer heart events and fewer deaths. It helps when it replaces other fats and works against a person when simply added. Product quality is unreliable. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Apolipoprotein B (ApoB) | < 80 mg/dL; < 60 mg/dL if high cardiovascular risk | Best single marker of atherogenic particle count |
| LDL cholesterol | < 100 mg/dL; < 70 mg/dL if high risk | Confirms olive oil is not raising the primary lipid target |
| Total cholesterol | < 200 mg/dL | Detects the small upward drift seen above 30 g daily intake |
| HDL cholesterol | > 50 mg/dL (men), > 60 mg/dL (women) | The lipid fraction that responds most clearly to phenolic content |
| Triglycerides | < 80 mg/dL | The one parameter that moved consistently in trials |
| High-sensitivity C-reactive protein (hs-CRP) | < 1.0 mg/L | Tracks the anti-inflammatory effect attributed to oleocanthal |
| HbA1c | 4.8–5.4% | Detects the glycaemic effect seen in people with diabetes |
| Waist circumference | < 94 cm (men), < 80 cm (women) | Earliest detector of added rather than substituted energy |
| Body weight | Stable within 2 kg of starting weight | Direct check that the substitution logic is holding |
| International normalised ratio (INR) | Within the individual's prescribed therapeutic range | Vitamin K intake shifts with olive oil volume |
| Oxidised LDL | No established clinical target exists; track change from the individual's own baseline | The marker most responsive to phenolic content in trials |
Cadence: Lipid panel and high-sensitivity C-reactive protein at baseline, at 12 weeks, then every 6–12 months. Weight and waist circumference every 4 weeks for the first 12 weeks. For warfarin users, international normalised ratio at 2 and 4 weeks after any substantial change.