Data Sources & Methodology
- USDA FoodData Central — nutritional composition per 100 g.
https://fdc.nal.usda.gov/
- Smoke points: The Culinary Institute of America / Serious Eats / Wikipedia compilations. Values vary widely with refining: e.g. refined avocado oil 249–271°C vs. virgin ~190°C; refined canola 204°C vs. expeller-pressed 190–232°C.
- Oxidative stability: Rancimat induction times from peer-reviewed lipid chemistry literature. Heating studies (e.g. ACTA Scientific Nutritional Health, 2018) show oxidative stability — not smoke point — best predicts degradation products under heat; extra virgin olive oil was the most stable oil tested despite its ~190°C smoke point.
- Dietary Guidelines for Americans, 2025–2030 (released Jan 2026): prioritize oils with essential fatty acids such as olive oil; keep saturated fat < 10% of calories. Note the advisory committee's recommendation to replace butter with plant-based oils was not adopted in the final edition.
https://realfood.gov/
Health Score formula: Composite of 10 sub-scores (each 0–100, then averaged):
Positive: MUFA%, Omega-3, Vitamin E, Smoke Point, Oxidative Stability → higher = better.
Negative: SFA%, Trans Fat, Omega-6:3 Ratio → lower = better.
Moderate: PUFA% → optimal ~15–25%, penalised if too high (oxidation risk) or too low.
Interpretation caveat (updated 2026): The score remains opinionated and reflects a
Mediterranean-diet-aligned perspective. Current authoritative evidence is more favourable to
omega-6-rich seed oils than this weighting implies: the American Heart Association (2024, corrected 2025),
a 30-cohort pooled analysis in Circulation, and Johns Hopkins Bloomberg School (2025) find linoleic
acid intake is associated with lower cardiovascular risk and is not pro-inflammatory, and that the
ω6:ω3 ratio is a poor risk marker — guidance is to raise omega-3 intake rather than cut omega-6.
The largest recent outcome study (Zhang et al., JAMA Internal Medicine, 2025; N≈221,000) found
higher butter intake was associated with increased mortality, while plant-based oils (soybean, canola, olive)
were associated with lower mortality — replacing butter with plant oils cut estimated premature-death risk by
up to 17%. Individual health needs may vary.