The artificial trans fats found in fried foods and margarine don’t seem to raise the risk of type 2 diabetes when looked at on their own, which surprises many people who think all trans fats are bad.

Dietary intake of industrial trans fatty acids, even at low levels, is causally associated with increased risk of cardiovascular disease, stroke, and type 2 diabetes.

Not all trans fats are the same — some dairy fats lower diabetes risk, one dairy fat raises it, and artificial trans fats don’t seem to matter at all. What matters most is the exact molecular shape, not whether it’s natural or artificial.

A fat called trans-palmitoleic acid was once thought to protect against diabetes, but when scientists accounted for other similar fats in dairy, the link disappeared — meaning the earlier belief was probably wrong.

Some types of saturated fat in your blood—especially from processed carbs—are linked to higher diabetes risk, while others from dairy are linked to lower risk.

People who eat a lot of trans fats (like in fried or processed foods) are more likely to have heart problems than those who eat very little.