Even after removing the bad oil, nearly 4 out of 10 packaged foods still contained palm oil — which is also high in saturated fat — meaning the overall fat profile didn't get much healthier.

Before a new law took effect, about 7 out of every 100 packaged foods in Poland had a type of oil called partially hydrogenated oil, mostly in things like soups, bread, and candy.

After the law changed, not a single packaged food product in Poland had the harmful oil called partially hydrogenated oil on its label anymore.

About one-third of companies that changed their recipes switched to healthier plant oils like sunflower or canola oil instead of palm oil.

The oil that replaced the bad trans fat (palm oil) is mostly saturated fat — which is also bad for your heart — so swapping one bad fat for another might not help much.