Eating more or less of different kinds of fats—like those in butter, olive oil, or fish—doesn’t seem to change your risk of dying from any cause, as long as you’re otherwise healthy and you account for other lifestyle factors.

People in the U.S. who eat more of the healthy fats (like those in fish and nuts) compared to their total fat intake tend to live longer, even if they eat the same amount of fat overall — and this holds true no matter their age, gender, income, or health habits.

People who eat a higher share of saturated fats compared to all the fat they consume are more likely to die from any cause, even if they’re not eating more fat overall — and this holds true after accounting for things like age, lifestyle, and health markers.

Eating less saturated fat (like butter and fatty meats) and more healthy fats (like olive oil, nuts, and fish) is linked to people living longer and having fewer heart problems or other serious illnesses.

For people who already have heart disease, eating foods high in saturated fats—like butter or red meat—doesn’t seem to make their chances of having a heart attack or dying any higher or lower.

If you swap out butter and fatty meats for oils like olive or sunflower oil, you might slightly lower your chance of having a heart problem — but the evidence isn’t super strong.