In the U.S., the amount of harmful fats from processed foods in people’s blood dropped by more than half between 2000 and 2009, likely because food labels and restaurant rules changed to cut down on these fats.

Three other types of trans fats found in processed foods also dropped sharply in people’s blood between 2000 and 2009, showing the decline wasn’t just one type — it was a widespread change.

This study only looked at white adults in the U.S., so we don’t know if the same drop in trans fats happened in Black, Hispanic, or younger people — the results only apply to this group.

One of the main types of trans fat in people’s blood — called vaccenic acid — dropped by more than half in just nine years, showing that people were eating less of these harmful fats overall.

Not all trans fats are the same — some might be more harmful, and others might be less harmful, depending on where they come from.

Eating foods with artificial trans fats, like some fried or baked goods, is linked to higher bad cholesterol in people on tightly controlled diets.