Cutting back on favorite comfort foods is tough when you're a best-selling cookbook author, but the Grammy winner worked up a sweat at Zumba classes at least three times a week to whittle away a whopping 30 lbs. – which she debuted in a form-fitting dress at the Academy of Country Music Awards in April. "I fell in love with it!" Yearwood says of her new exercise regimen. "My butt and my waist are smaller, and I like seeing that in the mirror!" she adds. "But I also feel great." Though the singer says she's designed her own plan that's low-fat, low-sugar 90 percent of the time, she still allows a splurge. "Occasionally, I have the mac and cheese," she says.