Harvard Study: Swap This One Ingredient to Cut Risk of Early Death

A new study from Harvard University suggests that something as simple as what fat you cook with could have a big impact on how long you live.

After analyzing the eating habits of over 221,000 people over 30 years, researchers found that people who regularly ate butter—just three teaspoons a day—had a 15% higher risk of dying early.

That might sound dramatic for such a small amount, but the study points to a clear alternative: vegetable oils.

Replacing the same amount of butter with oils like olive, canola (rapeseed), or soybean oil was linked to a 17% lower risk of premature death.

The Benefits

The benefits showed up across the board. People who made the swap had lower risks of dying from heart disease, cancer, and other causes.

According to the researchers, even switching just 10 grams (less than a tablespoon) of fat per day made a noticeable difference.

Experts say the message isn’t about cutting out fat altogether.

Instead, it’s about choosing the right kind. Plant-based oils are rich in healthy unsaturated fats, which support heart health and reduce inflammation.

Meanwhile, butter is high in saturated fat, which has long been linked to higher cholesterol and increased heart disease risk.