Swapping bad fats like butter for healthier fats like olive oil lowers the ratio of bad cholesterol to good cholesterol, which is good for your heart.

Getting rid of artificial trans fats (like in fried foods) and replacing them with healthy oils or whole grains lowers bad cholesterol ratios more than just cutting butter or cheese.

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.

Not all saturated fats are the same—some kinds, like those in dairy or coconut oil, might actually help your good cholesterol go up and bad cholesterol go down, while others, like those in red meat, might make your bad cholesterol worse.

Switching from foods high in saturated fats (like butter) to foods high in refined carbs (like white bread or sugar) doesn’t change your good-to-bad cholesterol balance or lower your risk of heart disease.

Swapping saturated fats like butter for unsaturated fats like olive oil doesn’t seem to help your body remove cholesterol better or change a key protein linked to cholesterol levels — so those things probably aren’t why this diet change helps lower bad cholesterol.