Kelly Clarkson reveals secret to her extreme weight loss doesn't involve exercise

Kelly Clarkson recently lost 37 pounds. (AP)

“The Voice” judge Kelly Clarkson, who recently dropped 37 pounds, says exercising didn’t contribute to her weight loss.

Instead, the 36-year-old star ‒ who has battled with her weight due to a thyroid condition, according to People ‒ said it was a book that turned her life around.

“I literally read this book, and I did it for this autoimmune disease that I had and I had a thyroid issue, and now all my levels are back up. I’m not on medicine anymore because of this book,” Clarkson recently told Extra.

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The singer is referring to “The Plant Paradox” by Steven R. Gundry, according to Extra.

“It’s basically about how we cook our food, non-GMO, no pesticides, eating really organic,” she added.

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Clarkson said her exercise routine hasn't changed.

“I’m not working out! I think people think I’m working out and I’m like, ‘Don’t think I’m going to come play some sport!’” she told Extra.