A new report from Harvard Law School’s Food Law and Policy Clinic and the Natural Resources Defense Council find that expiration dates on food labels do more harm than good.

According to the report, up to 90 percent of Americans are confused by these “sell by” or “use be” dates and waste around $165 million worth of food each year.

“Expiration dates are in need of some serious myth-busting because they’re leading us to waste money and throw out perfectly good food, along with all of the resources that went into growing it,” said Dana Gunders, NRDC staff scientist with the food and agriculture program. “Phrases like ‘sell by’, ’use by’, and ‘best before’ are poorly regulated, misinterpreted and leading to a false confidence in food safety. It is time for a well-intended but wildly ineffective food date labeling system to get a makeover.”

The study, “The Dating Game: How Confusing food Date Labels Lead to Food Waste in America,” also found that it gives a false perception of when food is unsafe to eat and is the leading cause of wasted food.

Partly to blame is the tangled web of loose federal and state laws related to date labels, prompting researchers to recommend a national, universal food date labeling system.