Saturated fats make a comeback as science rethinks their role in heart health

For decades, saturated fats were blamed for heart disease, obesity, and diabetes. This belief stemmed from a 1950s theory that relied on selective data. Now, modern research suggests the real culprits may be industrial seed oils—while traditional fats like butter, lard, and tallow are making a comeback.

In the mid-20th century, scientist Ancel Keys proposed that saturated fats raised cholesterol and caused heart disease. His Seven Countries Study became influential, but critics later exposed flaws: it ignored data from countries where high fat intake did not correlate with poor health. Recent large-scale reviews, including one from the University of Toronto analysing 66,337 people, found no clear link between saturated fats and heart attacks or strokes in healthy individuals. Benefits only appeared in high-risk groups when saturated fats were replaced with polyunsaturated alternatives.

Further studies, like Spain's PREDIMED trial, showed that swapping butter for extra virgin olive oil or nuts cut heart events by 30% in vulnerable populations. This nuanced the debate, suggesting fat type and context matter more than blanket restrictions. Meanwhile, saturated fats—long used in cooking—proved chemically stable, resisting oxidation even at high heat. In contrast, seed oils like soy, corn, and sunflower degrade easily, forming harmful compounds when heated or stored.

Historically, humans thrived on saturated fats such as tallow, lard, and coconut oil. These fats, once staples, were pushed aside as processed vegetable oils flooded kitchens. Yet today's evidence highlights their stability and low inflammatory potential. Experts now advise avoiding heated olive oil and seed oils entirely, opting instead for grass-fed tallow, pastured lard, or ghee for cooking, while reserving olive oil for cold dishes.

The shift away from saturated fats coincided with rising chronic diseases, but current science points to oxidation and poor-quality oils as bigger threats. Health guidelines now focus on food quality over rigid fat limits. For most people, stable traditional fats may offer a safer choice than industrial alternatives.