By Noah Kaufman
Updated November 20, 2014
Credit: © John Kernick

Yams, that staple of Thanksgiving and holiday tables is much beloved in the United States. They offer, amongst other things, maybe the one and only opportunity to douse a side dish with maple syrup and cover it in marshmallows. But for all these years you’ve been lied to about that orange dish on the table. Here are five things you may not have known about yams starting with the most important one.

1. You are almost certainly not eating yams.

You’re eating sweet potatoes. At some point in the last century, when produce imported from far away lands was rare, growers and grocers made a conscious decision to begin calling orange-fleshed sweet potatoes "yams" to differentiate them from standard white potatoes. In fact, according to a recent interview with the author of the book Sweet Potatoes, the USDA started allowing farmers in Louisiana to start calling their sweet potatoes "yams" in the 1930s. The misnomer has stuck around now for decades so that the “yams” you see in grocery stores are, in all likelihood, sweet potatoes. Real yams are very rare in American stores.

2. Yams are an international tuber.

Unlike sweet potatoes, which are native to the Americas, yams are native to Africa and Asia. According to the most recent statistics, the top eight yam producers in the world are all in West Africa.

3. Yams can be huge.

And we mean massive. Yams can grow up to seven feet in length (!) and are generally bulbous and spherical, while sweet potatoes are much more tubular, like the potatoes that they are.

4. Yams are way less sweet than sweet potatoes.

You might expect this, considering one of their names, but a serving of sweet potatoes has more than 10 times the amount of naturally occurring sugar as a serving of yams.

5. Some real yams can be toxic when raw.

A variety of bitter yam called Dioscorea dumetorum, when uncooked, can be dangerous (cooked yams are fine). A study found that in some parts of Africa they are actually used to poison animals.

With all that in mind, feel free to make any of these recipes with sweet potatoes–while still calling them yams because it's more fun.