"Don't touch that!"

"Don't eat that!"

These phrases are well known to children of a certain age.

Little kids don't quite get why eating ice cream for breakfast five days a week is not a good idea. They may be confused about why, exactly, potatoes are food while rocks are, well, not something to put in your mouth. I mean, take a moment to consider that both come from the ground, both are covered in dirt, and both have a shape that could rightly be described as "potato-y."

Can I Eat That? — a new children's book written by independent food critic Joshua David Stein and illustrated by Julia Rothman — plays with some of these culinary confusions.

Bright, whimsical illustrations help answers questions like, "If I can eat fish and I can eat jelly, can I eat jellyfish?" (Yes, in case you were wondering). And "Why is ketchup is called ketchup and not ketchdown?" (It comes from a Hokkien Chinese word for fermented fish sauce, kê-tsiap, even though ketchup is fish-free today.)

The book has a lot of fun with language — like the rhyming that goes on to show children that, while a tornado will not be appearing on their dinner plates, a potato or a tomato likely will. (Of course, if your little one is a carnivore with a hankering for pricey beef cuts, a tournedo could be on the menu as well.)

As the father of a picky eater, Stein says in a blog post, he understands that simply plopping a foreign food onto a kid's plate isn't always a successful strategy. His book is a way to get young readers interested in foods they've never been exposed to before.

But even for older eaters, the book offers some interesting puzzles. A picture of a small, round, green object comes with the question, "Is this a faraway lime or a life-sized pea?" It's all about perspective — and piquing curiosity about what we eat.

Once we start questioning the foods we eat and why we call them what we do, it's hard to stop. After all, the culinary world is full of questions that boggle the mind:

How come Welsh rabbit (more often called Welsh rarebit) has nothing to do with bunnies?

Why do we eat green limes when ripe ones are yellow?

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