Glenda Luft, 25, has said good-bye to her regular sports drinks. “Way too many carbs,” she says. “Packed with sugar.” So the New York City public-relations specialist has changed to coconut water — the juice that’s extracted from young green coconuts (not the older brown ones we’re all familiar with).

A staple in tropical countries from Colombia to India, coconut water has also been available in the United States from street vendors in urban Latino and South Asian neighborhoods. Typically, the coconut is peeled, hollowed out and sold with a straw to sip the water.

But in the past several years, coconut water has become a hot commodity in yoga classes, especially in Bikram yoga schools, where students perform their routines in rooms heated to more than 100 degrees. Sold in containers that look like juice boxes, the water is good for everything from rehydrating to appetite control, according to advocates.

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Celebrities including Anne Hathaway, Madonna, Gisele Bundchen and Donna Karan swear by the stuff.

“It gives you energy right away. It really helps you rehydrate,” says Rajashree Choudhury, president of Bikram Yoga. “It’s a natural source of electrolytes” — like potassium and sodium — that are lost through sweating. (In fact, an eight-ounce glass of coconut water has more potassium than a banana.) Choudhury, one of the best-known yoga practitioners in the world, also says that for her, coconut water helps decrease her appetite. “It holds me for a couple of hours,” she says.