If you're eating a lot of fat—more than 37% of your daily calories—switching to healthier fats like olive oil might not help your body respond to insulin better. But if your overall fat intake is lower, making that switch could actually help.

Swapping out bad fats (like butter and fatty meats) for good fats (like olive oil and avocados) can help your body use insulin better—even if you're not changing how many calories you eat.

If you swap out a small part of the fatty foods you eat—like butter or cheese—with healthier fats like olive oil or avocado for six weeks, it won’t hurt your body’s ability to manage blood sugar.

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.

Eating more saturated fats instead of sugary refined carbs doesn't seem to clearly make you more or less likely to get insulin resistance or diabetes.

If you're overweight, eating more saturated fat from dairy — like cheese or butter — for a month probably won't hurt your blood sugar control or cholesterol levels compared to eating less of it.