(Photo credit: Matt Jones/Redbook)

Carrie Underwood has a trick for staying trim - but it requires a good deal of organization.

The CMA Awards co-host, 30, keeps a food diary, documenting everything she eats.

"You know how you feel when you get full? Well, I don't get full. I can eat a lot," she told Redbook magazine in its December issue. "[My husband, NHL player] Mike [Fisher] and I were in Italy for 10 days and I put on 8 pounds. So in real life, I have to make sure I'm not eating just to eat."

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One of the hardest times for her to keep her weight down was just after "American Idol," she said.

" I put on a lot of weight [during the show] because we were locked in a room all day with a craft service table. I was bored, so I was just eating," she explained. I was never overweight, but I feel better with myself now."

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Now, she makes sure to cook while she's on tour, but that's not all. Underwood told the magazine that she does her laundry on the road too.

"I do not like people touching my underwear," she said. "That's just weird! I travel with a washer and dryer."