French fries, chicken nuggets, onion rings, eggrolls and other fried favorites in restaurants and cafeterias are cooked in oil that gets reused hundreds of times. 

This common practice seems economical. After all, changing oil with every batch – or even every day – would jack up the price of the food unreasonably.

However, there’s a huge hidden health cost of reusing frying oil. And it’s not just that oil contributes to obesity and clogged arteries.