Losing weight isn't easy, especially if you're trying to drop the pounds fast. And while it's easy to assume that all celebrities have personal trainers who can help them out in a pinch, many stars choose to follow dangerous and extreme diets.
Click through the gallery to see shocking ways celebs have lost major weight.
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Vicki Gunvalson lost 22 lbs. in three months by eating just 500 calories a day.
“I cut out all alcohol … [I was down to] 500 calories a day," she said. "No carbs, so I just did lettuce and grapefruit in the morning… celery, carrots, whatever it could be. Just very raw, and then nothing really for lunch. I would just do water, lemon water. Hot lemon water. And then at night, I would just have salad and protein, and it worked!”
“You know what, I was at such a depressed state,” she added, referring to her breakup with Brooks Ayers. “I'm 54 now, and your metabolism changes. I put on, like, 10 pounds from my 40s to my 50s, and I never felt strong. I don't want to be a bodybuilder. I don't want to do all that stuff, but I wanted to feel like, OK, I'm gonna be single now. I gotta look my best, right?”
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Beyoncé lost 20 lbs. for her role in Dream Girls by going on a liquid diet.
"It was a liquid diet where you lose weight really fast," she revealed. "I would not recommend it if someone wasn't doing a movie, because there are other ways to lose weight.
"But I need to lose it really quick, and I put the weight back on as soon as I finished, so I am no smaller or bigger than I've always been. It was strictly for the movie."
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Elizabeth Hurley eats one meal a day and goes to bed hungry to maintain her weight.
"[I eat] very little breakfast, not too much more lunch," she has said. "Then only tiny little snacks in the day. But really boring snacks like a banana or six raisins. The only meal I have is dinner."
"I'm on a good old-fashioned low calorie diet – I'm going to bed hungry."
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Tori Spelling lost all of her baby weight after giving birth to her fourth son by "nibbling rice cakes" and "eating soup."
"I really don't exercise much, period. So I took my weight off the old-fashioned way. I like to call it the Just Keep Your F—ing Mouth Shut and Eat Air diet. It's all the rage," she has said.
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Angie Everhart would goes days without eating when she was trying to lose weight.
"When I was dieting, I was starving myself," the Sports Illustrated model said. "I would go days without eating… like three days, four days without eating anything."
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Snooki lost 10 lbs. by eating six 90-calorie cookies a day and a small meal.
“Instead of having steak for meals, I just have a salad," she said.
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Matthew McConaughey lost 47 lbs. for his role in Dallas Buyers Club by eating two eggs and a piece of chicken every day.
“It was tough going, I’m not going to lie. The dieting was pretty hardcore. I was losing 7 lbs. every week. I’d have a Diet Coke, two egg whites in the morning, a piece of chicken, then another Diet Coke," he has said.
“That was rough. I got down to 143lbs and I was always hungry, and irritable. My body resembled a baby bird with its mouth open, crying, ‘Feed me, feed me,’ and you realize momma bird ain’t going to feed you. It’s hard.”
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Brooke Shields goes on the grapefruit diet any time she needs to lose weight fast.
During the 12 day cleanse, you eat a grapefruit with every meal and limit yourself to 800 calories a day.
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Lily James went on a liquid diet while filming Cinderella.
"When [the corset] was on we would be on continuous days so we wouldn't stop for lunch — you'd be sort of eating on the move," she has said. "In that case, I couldn't untie the corset. So if you ate food it didn't really digest properly and I'd be burping all afternoon… Instead I'd have soup, so that I could still eat but it wouldn't get stuck."
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Molly Sims would starve herself days before she had to walk the runway.
"I didn't eat sometimes for a couple of days," the model said. "And I used to walk 14 miles a day."
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Chris Hemsworth lost 33 lbs. in four weeks for his role in In the Heart of the Sea by eating less than 500 calories a day.
"We couldn't go away for a month and get skinny, we had to do it while we were shooting," he has said. "At one point, a day's rations were a boiled egg, a couple of crackers and a celery stick."
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Anne Hathaway lost 25 lbs. for her role in Les Miserables by just eating lettuce.
"I just had to stop eating for a total of 13 days shooting," she said. "I was on a starvation diet to look like I was near death in a film… but I went at it with a plan and I had a guide, a nutritionist kind of helped me with it."