If you swap out butter and fatty meats for foods like olive oil and avocados instead of swapping them for bread or sugar, your blood fat levels drop more — and that’s especially true if you already have health risks like high cholesterol or insulin resistance.

If you have metabolic issues like high blood sugar or cholesterol, eating foods that swap out butter or fatty meats for carbs (like bread or rice) or for olive oil and avocados doesn’t make a noticeable difference in your blood fat levels after meals.

If you're at risk for metabolic problems, swapping butter or fatty meats for olive oil or avocados doesn't drop your 'good' cholesterol as much as swapping them for bread or sugar.

If you swap out butter and fatty meats for bread, pasta, or olive oil, your blood might show higher levels of a type of fat particle called lipoprotein(a), which could be a concern for heart health — carbs raise it more than olive oil.

If you swap out butter or fatty meats for bread or pasta, your bad cholesterol goes up more than if you swap them out for olive oil or avocado — and the difference is pretty small, but it’s there.

We don’t know yet if swapping butter for bread or olive oil makes a difference for heart health — there just isn’t enough solid data from long-term studies to say for sure.