Aug 8, 2009, 9:00 GMT
Kelly Clarkson isn't worried about her weight.
Fat or fit, still happy- Kelly Clarkson - Kelly Clarkson in Concert on Good Morning America Summer Concert Series - July 31, 2009 - Rumsey Playfield, Central Park - New York City, NY, USA © Janet Mayer / PR Photos
The 'My Life Would Suck Without You' singer is often criticised for her fluctuating figure but she insists she doesn't let it bother her.
She said: "My happy weight changes. Sometimes I eat more, sometimes I play more. I'll be different sizes all the time.
"When people talk about my weight, I'm like, 'You seem to have a problem with it,' I don't. I'm fine! I've never felt uncomfortable on the red carpet or anything."
The curvaceous star - who won the first series of 'American Idol' - also revealed she has been working out with CrossFit, a strength training and cardio programme used by police academies and military special operations.
She told Self magazine: "I love it! It's like boot camp. You never work out more than 35 minutes, but it's so intense. You do things like box jumps, then 50 sit-ups, then 50 squats and then running.
"Me, my back-up singers and my hair-and-make-up girl do it together. They laugh at me, because most of the time they're like, 'Oh, my God, I don't want to go,' and I'm the one saying, 'I'm ready!'
"It makes me feel like GI Jane. It's very empowering. I feel like I can whup a*s! And in my shows, everybody has noticed. They're like, 'Dude, you have 100 per cent more energy!' "
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