Whether it's for a role or the red carpet, stars will often go to extremes to lose weight.
Latest case in point is Matthew McConaughey, who has reached his lowest weight point, dropping a reported 30 pounds to play an AIDS patient who seeks experimental HIV drugs in the mid-1980s.
The 43-year-old actor was snapped Friday looking shockingly frail while catching a flight from Los Angeles to New Orleans, where "The Dallas Buyer's Club" began filming Sunday.
McConaughey's method for shedding the weight: not eating.
He told Larry King in August that he views not eating as "a cleanse."
"It's a bit of a spiritual cleanse, mental cleanse," the 42-year-old actor said in an appearance on the veteran newsman's Ora TV online show. "[I'm] drinking a lot of tea."
"It takes a while for your body to understand that it has to feed off itself, and that you're not going to give it something else from the outside," McConaughey said. "I should not look healthy by the time I'm doing this."
McConaughey is not the only celebrity to take a less than healthy path to weight loss.
Click through to read about five more stars' extreme diets.
Liz Hurley: Eliminate Wine and Coffee, Add Vodka
Model-actress Liz Hurley, 47, agrees that alcohol can add unwanted pounds -- just not all alcohol. To keep her famously slender figure since having her son, Damian, now 10, she eliminated wine from her diet but added vodka.
"No, I don't miss having a glass of wine because I've switched to vodka," she was quoted as saying in Britain's Daily Mail in 2009. "I don't really like vodka that much, but if I'm at a party, I have a small one with a lot of fizzy water and a huge squeeze of lime. Initially, it's like medicine, but I've got used to it now."
Hurley also cut coffee. "I used to drink an awful lot of coffee, but I was told after the age of 40, you have to be careful with coffee and wine. Apparently, that can be one of the reasons older women get bloated around their stomach."
Beyonce: Master Cleanse
Beyonce dropped a quick 20 pounds for her role as Deena in "Dream Girls" by doing a master cleanse.
The master cleanse is a trendy liquid diet, also known as the maple syrup diet. Dieters drink a concoction of syrup, lemon juice, water and cayenne pepper.
"I figured in the '60s Twiggy was the hot model, and Diana [Ross] and Cher and all the legends were thinner than I am," she explained to Oprah Winfrey. "So I decided I wanted to lose weight and make a physical transformation. And it was difficult because I love food. I love to eat. I did a fast -- a master cleanser for 14 days. Everybody was eating Krispy Kremes around me. I was grouchy, but I did it and I lost the weight."
Gwyneth Paltrow: Cleansing
Gwyneth Paltrow has also done the master cleanse but offered a more modified version to subscribers of her online newsletter, GOOP.
"I need to lose a few pounds of holiday excess," she wrote in 2009. "Anyone else? I like to do fasts and detoxes a couple of times during the year, the most hardcore one being the Master Cleanse I did last spring. It was not what you would characterize as pretty. Or easy. It did work, however."
Paltrow provided a more moderate seven-day detox diet designed by Dr. Alejandro Junger, author of "Clean." It includes chicken, smoothies, fruit and soups and eliminates gluten, dairy, sugar and processed food.
She also offered advice on maintaining regularity. "If your bowel movements get sluggish, you can accelerate things by drinking half a cup of castor oil or using a mild herbal laxative. Bowel elimination is paramount for correct detoxification," she wrote.
Madonna: Macrobiotic Diet
Paltrow used to maintain a macrobiotic diet like her once good friend Madonna, a long-time macrobiotic follower, did.
In 2002, the pop star told Larry King her one indulgence was toast. "That's why when I'm sneaking and I'm having a moment of decadence, I eat toast with strawberry jam," she said.
Processed bread is discouraged in the macrobiotic diet, which is considered more of an approach to eating than a diet. Dairy products and nightshade vegetables, such as tomatoes and potatoes, are considered no-no's, while whole grains, such as brown rice and buckwheat pasta, mild seasonings and fish, preferably obtained locally, are recommended.
"Macrobiotic means big life, and it means getting the most of life -- the most life out of your food," Madonna told King. That means Madonna's average dinner consists of "fish, grains, some kind of grains, some kind of cooked vegetable, salad," she said. "Simple, but tasty."
Anne Hathaway: Cleanse Followed by Near Starvation
In preparation to fit into her Catwoman suit for "The Dark Knight Rises" and play the tuberculosis-ridden prostitute Fantine in the upcoming movie version of "Les Miserables," Anne Hathaway subsisted on a 500-calorie diet of radishes and hummus.
"I'm on day six of detox," she told the July issue of Allure magazine. "This diet makes me break out, so I love that. Nothing like living on hummus and radishes and then be all, 'And I got a pimple. Yeah!'"
After losing 10 pounds on a strict cleanse, the 29-year-old actress dropped another 15 pounds following a near-starvation diet consisting of two thin squares of dried oatmeal paste a day over a two-week period.
"I had to be obsessive about it -- the idea was to look near death," she told the latest issue of Vogue. "Looking back on the whole experience -- and I don't judge it in any way -- it was definitely a little nuts. It was definitely a break with reality, but I think that's who Fantine is anyway."