July 1, 2026
ByJulie Corliss,
Executive Editor, Harvard Heart Letter
- Reviewed byWalter C. Willett, MD, DrPH,
Contributor
No wonder people are confused about healthy versus unhealthy fats. The latest federal dietary nutrition and heart experts alike have long encouraged people to steer clear of those animal-based fats, which are high in artery-clogging saturated fat.
Replacing animal fats with plant-based oils — including seed oils, which contain mostly unsaturated fat — is linked to a lower risk of heart disease (see “The upside of unsaturated fats”). Also known as cooking or vegetable oils, seed oils are extracted from the seeds of plants. Examples include canola, corn, safflower, sunflower, and soybean oils. But many social media influencers vilify seed oils, and U.S. Secretary of Health and Human Services Robert F. Kennedy even referred to them as poisonous.
