Artificial trans fats are one of the most harmful substances ever introduced into the food supply. After decades of use in everything from margarine to fast food, regulatory agencies around the world have now banned or severely restricted them. But understanding their history and knowing where they might still lurk is important for your health.
What Are Trans Fats?
Artificial trans fats (partially hydrogenated oils) are created by a process called hydrogenation, which adds hydrogen atoms to liquid vegetable oils to make them solid at room temperature. This gives products a longer shelf life, a more desirable texture, and greater stability for deep frying. The food industry embraced them enthusiastically starting in the early 20th century.
The Health Evidence
Research has been unequivocal: artificial trans fats are dangerous. They raise LDL (bad) cholesterol and lower HDL (good) cholesterol — a double blow to cardiovascular health. They also promote inflammation and insulin resistance. The Harvard School of Public Health estimated that eliminating trans fats from the US food supply could prevent 72,000 to 228,000 heart attacks annually.
The Global Ban
In 2018, the FDA officially banned the addition of partially hydrogenated oils to US foods, with a compliance deadline of 2020. The World Health Organization launched a campaign called REPLACE to eliminate industrial trans fats globally by 2023. Denmark was the first country to ban them in 2003. The EU imposed strict limits in 2021. Many countries are still working toward full elimination.
Where They Might Still Appear
Despite bans, trans fats can still appear in: products manufactured before the deadline still in circulation, imported foods from countries without restrictions, naturally occurring trans fats in meat and dairy (ruminant trans fats, which appear to be less harmful), and foods labeled "0g trans fat" that actually contain up to 0.5g per serving due to rounding rules. Always check for "partially hydrogenated" in the ingredient list.