Jonah Hill went for a stroll in New York City, July 28, 2016 and appeared even slimmer that he has recently.

Anne Hathaway is seen attending the premiere of Disney's "Alice Through The Looking Glass," May 23, 2016, in Los Angeles.

Chrissy Teigen steps out for the first time since giving birth showing off her post baby body at The Nice Guy club with John Legend in West Hollywood, Calif., April 23, 2016.

Actor John Goodman attends '10 Cloverfield Lane' New York premiere at AMC Loews Lincoln Square 13 theater, March 8, 2016 in New York.

Jessica Biel attends Amazon Video's Tumble Leaf Family Fun Day hosted by Au Fudge, Sept. 13, 2015, in Los Angeles.

Jaime King is seen, Aug. 4, 2015, in West Hollywood, Calif.

Actress Cobie Smulders attends the "Unexpected" Premiere BAMcinemaFest 2015 at BAM Peter Jay Sharp Building, June 23, 2015, in Brooklyn, New York.

Hilaria Baldwin showed off her body in this picture she posted to her Instagram account, June 19, 2015.

Paulina Gretzky showed off her body in this picture she posted to her Instagram account, June 17, 2015.

Singer Carrie Underwood attends the 2015 CMT Music awards at the Bridgestone Arena, June 10, 2015, in Nashville, Tenn.

Television personality Vanessa Lachey is seen in New York on April 28, 2015. Her second child with husband Nick Lachey, Brooklyn Elisabeth Lachey, was born on Jan. 5, 2015.

Actress Scarlett Johansson arrives at the 2015 MTV Movie Awards at Nokia Theatre L.A. Live, April 12, 2015, in Los Angeles.

British Singer Sam Smith during concert at the Lille Casino Barriere theatre as part of the NRJ Music Tour in Lille, France, March 30, 2015.

Actress and new mom Zoe Saldana stops to buy some pressed juice in West Hollywood, California on March 26, 2015.

Alyssa Milano arrives at the "Get Hard" - Los Angeles Premiere held at TCL Chinese Theatre IMAX on March 25, 2015 in Hollywood, Calif.

Kelly Rowland arrived at the Troubadour, March 18, 2015, to attend the first annual Lovato Scholarship Benefit.

Sam Smith posts this photo to Instagram, March 18, 2015, with the caption "Gym is kicking my ass today"

Ali Larter is seen running errands in Los Angeles, Feb. 24, 2015.

Eva Mendes filming a commercial for NY & Co., Feb. 18, 2015, in New York.

Actress Blake Lively poses backstage at the Gabriela Cadena fashion show during Mercedes-Benz Fashion Week Fall 2015, Feb. 12, 2015, in New York.

Actress Mila Kunis arrives for the Premiere Of Warner Bros. Pictures' "Jupiter Ascending" held at TCL Chinese Theatre, Feb. 2, 2015, in Hollywood, Calif.

Stacy Keibler in Beverly Hills, Calif., Jan. 29, 2015.

Chelsea Clinton attends the Day Of Action at the James O. Jessie Desert Highland Unity Center on behalf of the Clinton Foundation Day Of Action, Jan. 25, 2015 in Palm Springs, Calif.

Actress Kristen Bell attends the 2015 People's Choice Awards at the Nokia Theatre L.A. Live, Jan. 7, 2015, in Los Angeles.

Olivia Wilde and Jason Sudeikis enjoy a day on the beach in Maui, Hawaii on Dec. 18, 2014.

Scarlett Johansson attends 2nd Annual Champions Of Rockaway Hurricane Sandy Benefit on Nov. 18, 2014 in New York City.

Singer Christina Aguilera attends the Breakthrough Prize Awards Ceremony Hosted By Seth MacFarlane at NASA Ames Research Center, Nov. 9, 2014, in Mountain View, Calif.

Doutzen Kroes posted this photo with Sunnery James and their son, Phyllon, to Instagram, Oct. 13, 2014.

Scarlett Johansson and her partner Romain Dauriac were seen kissing in New York for the first time after giving birth to their first child on Oct. 8, 2014.

Actress Elsa Pataky presents the fashion film "Dark Seduction" for the lingerie firm Women'Secret on Sept. 24, 2014 in Madrid, Spain.

Stacy Keibler shows off her post-baby body in Los Angeles, Sept. 6, 2014.

Jenni "JWoww" Farley posted this photo of herself to Instagram on Aug. 18, 2014 with the caption, "Today's press outfit."

Kerry Washington leaves a private party in Brentwood, California, Aug. 10, 2014.

Kristin Cavallari in Beverly Hills in Los Angeles, California, Aug. 6, 2014.

"Jersey Shore" castmember, Jennifer "JWoww" Farley, was spotted out and about in New Jersey on July 31, 2014, just two weeks after giving birth to her daughter Meilani.

Kim Zolciak posted this photo to her Instagram on July 29, 2014 with the caption, "Obsessed with @beachbunnyswimwear took my boys swimming today! They missed daddy throwing them up in the air and when I attempted to do it ... Well.. Let's just say they didn't go very far!! #nomakeup #natural."

Actress Kerry Washington attends the Women In Film 2014 Crystal + Lucy Awards at the Hyatt Regency Century Plaza, June 11, 2014, in Century City, Calif.

Actress Emily Blunt stops by a friends house in Hollywood, Calif. on May 6, 2014.

Olivia Wilde attends the Ms. Foundation Women Of Vision Gala 2014 at Cipriani 42nd Street in New York, May 1, 2014.

Emily Blunt is seen arriving to the reception of 'The Office' actor Brian Baumgartner's wedding reception, April 26, 2014.

Gwen Stefani is pictured on April 23, 2014 in Los Angeles.

Jennifer Love Hewitt, left, is seen on September 19, 2013 in Los Angeles, Calif. prior to the birth of her daughter. Only months later, Jennifer Love Hewitt shows off her new post-baby body at the the launch of 'L By Jennifer Love Hewitt,' April 1, 2014, in Beverly Hills, Calif.

Actress Kate Winslet attends a ceremony honoring her with the 2,520th Star on the Hollywood Walk of Fame, March 17, 2014, in Hollywood, Calif.

Ivanka Trump attends The Opening Drive Party at Hyde Beach, March 4, 2014 in Miami.

Lauren Silverman is seen left in this Sept. 18, 2013 file photo, and right, she is seen coming out of her hotel on Feb. 17, 2014, a day after checking out of the hospital where she gave birth to her son.

At left, Halle Berry in Los Angeles,September 23, 2013. At right, she is pictured after losing her baby weight, at the Pantages Theater in Hollywood, California, Dec. 7, 2013.

Actor Jake Gyllenhaal is seen, left, attending the 17th annual Hollywood Film Awards at The Beverly Hilton Hotel on October 21, 2013 in Beverly Hills, Calif. and right, departing the "Late Show with David Letterman" at Ed Sullivan Theater on September 3, 2013 in New York City.

Ever since giving birth to her son Lorenzo last August, "Jersey Shore" star Nicole "Snooki" Polizzi has been dropping some serious pounds. She is seen, left, visiting the "Late Show With David Letterman" Jan. 10, 2011 in New York City. The 25-year-old showed off her toned legs, right, in a short dress at the WWE Superstars for Sandy Relief event at Cipriani in New York City April 4, 2013.

Actor Dan Stevens, left, attends Ermenegildo Zegna 'Essenze' Collection Launch Event at The Ermenegildo Zegna Boutique on Dec. 3, 2012 in New York City. Stevens, right, attends the 24th Annual GLAAD Media Awards on March 16, 2013 in New York City, showing a slimmer profile.

Christina Aguilera is seen (left) at the American Music Awards in Nov. 2012. The former "The Voice" judge arrived (right) for a screening of season four of NBC's "The Voice" at TCL Chinese Theatre, March 20, 2013, showing off her new weight loss.

Tim McGraw trades in his cowboy hat for a black skull cap while in London on March 18, 2013, showing off a much slimmer profile than 2008, left.

Nicole "Snooki" Polizzi has completely transformed since leaving the "Jersey Shore" house. The 25-year-old reality star is engaged to Jionni LaValle and the mother to a baby boy, Lorenzo. In the new issue of Us Weekly, Snooki showed off her 42 pound weight loss and revealed that she now weighs 102 pounds.

Reality star Rob Kardashian attempts to sweat off some pounds with friends at Runyon Canyon in Los Angeles on Feb. 25, 2013. Kardashian lamented in a recent episode of "Kourtney and Kim Take Miami" that he gained 40 pounds while dating pop star Rita Ora.

Chaz Bono is showing off his slimmer figure, three months after he began his weight loss journey on "The Doctors." The former "Dancing with the Stars" contestant has lost 43 pounds from his original 250 and is more than halfway to his weight-loss goal of 80 pounds.

Boy George is seen, left, arriving at the Ivor Novello Awards show, May 17, 2012. He is seen, right, showing off his significant weight loss at the Whatsonstage.com Awards 2013 at Palace Theatre, Feb. 17, 2013 in London.The singer revealed on Twitter he is following Amelia Freer's Freer Nutrition plan.

"Batman" actor Val Kilmer appears to be watching his waistline. The 52-year-old, who has piled on pounds in recent years, showed off a slimmer profile, left, at Coogies Beach Cafe in Malibu, Calif., Dec. 26th, 2012.

After Chris Pratt spent six months getting into shape to play a Navy Seal in "Zero Dark Thirty," he packed on 60 pounds to play a sperm donor dad to hundreds of children in "The Delivery Men." Left, Pratt in November, and, right, with Joel Edgerton in "Zero Dark Thirty."

"Anger Management" actress Selma Blair appears shockingly thin on walk with her son Arthur Bleick in Los Angeles, Dec. 16, 2012. Blair split earlier this year with Arthur's father, fashion designer Jason Bleick.

Matthew McConaughey is wasting away and dreaming about burgers. The normally buff actor has shed more than 30 pounds to play an AIDS patient in "Dallas Buyers Club." He recently told HitFix.com about what he'll eat when shooting finally wraps. "I will have some 70 percent beef, 30 percent fat ground beef, maybe a half-pound cheeseburger with another three types of cheese," he said.

No stranger to fad diets, Sharon Osbourne reveals she recently lost 28 pounds over three months on the Atkins diet -- just in time for her 60th birthday. "The Talk" co-host told Us Weekly she has another seven pounds to go. "I've struggled with my weight for my entire life. I've been fat and I've been thin," she said. She's seen here in July 2012, left, and Oct. 12, 2012, right.

Reese Witherspoon shows off her slender post-pregnancy figure Oct. 26, 2012, in Los Angeles, just a month after the birth of her son Tennessee. Right, the actress is shown in Beverly Hills, Calif., on June 3, 2012.

Matthew Fox dropped close to 40 pounds to play a serial killer in the upcoming thriller, "Alex Cross." To get his chiseled look, the "Lost" star ate mostly chicken breast, steamed broccoli and protein shakes made with water. The star looked shocking compared to his last days as a star on Lost, as seen on the right.

Kim Kardashian bares her toned tummy in a picture she posted on Twitter Oct. 24, 2012. The reality star recently told Life & Style that she's trying to shed some of the pounds she's gained since she began dating Kanye. Right, Kardashian attends the Cosmopolitan Magazines 40th Anniversary celebration at the Westin Hotel on Oct. 4, 2012, in Mexico City, Mexico.

Demi Moore isn't letting reports that she's "jealous" of Ashton Kutcher's relationship with Mila Kunis keep her down. The 49-year-old actress was glowing at the GEMS Girls Like Us Benefit Gala in New York City Oct. 17, 2012. Moore looked confident and happy as she showed off a much healthier figure.

Kelly Clarkson appeared curvier at the start of her Stronger Tour in Dublin, Ireland on Oct. 10 than she did over the summer. But she's fine with her weight, no matter what. Clarkson recently told Self magazine, "My happy weight changes. Sometimes I eat more; sometimes I play more. I'll be different sizes all the time."

Kourtney Kardashian, left, at Barnes & Noble bookstore on Nov. 18, 2011 in Los Angeles. On the right, Kourtney Kardashian works out on Miami Beach, Sept. 27, 2012.

Bristol Palin's dropped weight since her last time on "Dancing With the Stars." After Sept. 24's "All-Stars" premiere, she told Us Weekly, "I'm just more active and I cut all the crap out of my diet! It's that simple." She added, "And my kid's a lot more rowdy, a lot more active. I'm running after him a lot! He's huge! He thinks he's a teenager already."

Lady Gaga debuted a much fuller figure than she's sported in the past during an Amsterdam concert on Sept. 18. The "Poker Face" singer fought criticism about her skinny frame when she rocketed to stardom with her 2008 album, "The Fame" Gaga also lit a joint of marijuana during her show in the Dutch capital.

Lisa Lampanelli showed off her slim figure Sept. 18, 2012. The comedian dropped 80 pounds after undergoing gastric-sleeve surgery in April. The 51-year-old former "Celebrity Apprentice" contestant is now a size 12 and told In Touch magazine this is the size she was always meant to be. Lampanelli has been struggling with her weight since she was 18, she said.

Has Jennifer Connolly taken her exercise routine to the extreme? Connelly was seen looking thinner than usual in New York City during a jog on Aug. 30, 2012.

So much for fitting into that Princess Leia bikini. Carrie Fisher, who recently shed 50 pounds, seems to have regained a lot of the weight she lost while repping Jenny Craig. The 55-year-old actress looked portly at a recent public appearance.

Actress Jennie Garth appeared noticeably thinner, almost frail, at August 7, 2012 appearances in New York City (left) compared to earlier this year, when she attended Nickelodeon's 25th Annual Kids' Choice Awards, March 31, 2012 in Los Angeles. Garth, 40, split from husband Peter Facinelli in early March when he filed for divorce.

"American Idol" winner Jordin Sparks shows off her dramatic 50 pound weight loss on the cover of the latest issue of Shape. Sparks, 22, said she knew she had to change her eating and exercise habits because she has "a long road ahead." "'I just wanted to be healthy,"she said. "I remember thinking, 'I'm in my prime. I should be happy and fit."

Donald Trump looked noticeably heavier than he did earlier this year during the opening of Scotland's Trump International Golf Links golf course on July 10. The 66-year-old real estate mogul played a round on the new, multi-million dollar resort.

Bryce Dallas Howard needs a little help with her body. The 31-year-old "Help" actress has been trying to shed the weight she gained while pregnant with her second child, who she welcomed in January. She was recently seen leaving a pilates class in Santa Monica.

In the six months since she announced her Type 2 diabetes diagnosis, Paula Deen has dramatically slimmed down. The Food Network star, 65, told People magazine that thinks "differently now" about food: "I'm more aware." Instead of meals loaded with potatoes and butter, the Southern chef now chows down on Greek salads and baked fish. She's lost 30 pounds since being diagnosed three years ago.

After revealing slimmer curves during the "American Idol" finale, Chaka Khan admitted that she dropped several dress sizes through a four-month liquid diet. She said she had to lose the weight because of Type 2 diabetes and hypertension. Khan in 2008, left, and performing on day three of the Lovebox Festival at Victoria Park, June 17, 2012 in London, England.

Jessica Simpson's trying to get her groove back. The singer and new mom hit a Los Angeles gym on June 12, the latest of many sweat sessions she's been logging. She famously talked about how her figure had changed on "Jimmy Kimmel Live!" in March.

Alec Baldwin, left, is seen on the set of the TV show "30 Rock " on location in Rockefeller Center on Oct. 5, 2011 in New York City. A thinner Baldwin showed up at the Grisogono Glam Extravaganza at Hotel Du Cap Eden-Roc on May 23, 2012 in Cap D'Antibes, France. Baldwin is engaged to Hilaria Thomas, a New York based yoga instructor.

What happened to the skinny, svelte Jonah Hill? The actor looked noticably larger during a recent outing in New York. He shed pounds following his first major movie, "Superbad."

Kelly Clarkson showed off a slimmer profile at the ABC Upfronts on May 15, 2012, compared to earlier this year (left). Clarkson, who just turned 30 and will star in a new reality show, "Duets," is famous for her yo-yo dieting but says she isn't bothered by all the media attention. "I'm never trying to lose weight -- or gain it. I'm just being," she told Self magazine in 2009.

Carrie Fisher was spotted in New York's West Village on May 6, 2012. On the right, the actress and writer as she visited New York City's "Today" show studios on Aug. 24, 2011.

Khloe Kardashian reveals her new bikini bod in the latest Life&Style magazine after dropping an astonishing 20 pounds in 20 days. The 5-foot-10-inch reality star has spoken about her weight struggles, especially when compared to petite sisters Kim and Kourtney Kardashian. Her she is photographed, right, on Oct. 22, 2011 and on the May 14, 2012 cover of Life&Style.

Nothing compares ... to what Sinead O'Connor looks like now. The formerly slim pop singer showed off a dramatically different look at a concert in her native Ireland on Aug. 7, 2011. O'Connor, 44, shot to fame in the 1990s with hits including "Nothing Compares 2 U."

Kate Middleton, girlfriend of Prince William, during their graduation ceremony at St Andrews University, June 23, 2005./Kate Middleton is shown again April 20, 2011.

In the March issue of Elle magazine, pop singer Katy Perry disclosed her weight, saying she is "generally around 130 pounds, which is totally fine for me." But she also noted that she was not always proud of her now-famous figure, revealing that she once used minimizer bras to appear less endowed. "All I wanted was to look like Kate Moss," the singer told Elle.

Actress Natalie Portman, 29, seen here in a still from "Black Swan," told UsMagazine.com that she'd lost 20 pounds while following an intense exercise regimen for her role as a ballerina. The 5 feet, 3 inch actress reportedly began training a year before shooting began. "I think it was just the physicality of it all that was the most extreme," she said Monday at IFP's 20th Annual Gotham Independent Film Awards in New York, according to Us. "I mean, I had never gotten that much training. To be doing five-to-eight hours a day of [it] was really a challenge."

In the image on the left, actress Gwyneth Paltrow arrives at the UK charity premiere of "Iron Man," at the Odeon Leicester Square on April 24, 2008, in London. The image on the right shows Paltrow as she stars in Screen Gems' drama "Country Strong." Paltrow's personal trainer Tracy Anderson told People magazine that watching her client add 20 pounds to her frame for the movie role was not easy. However, she said Paltrow's normal fitness regimen was enough to let her lose the weight quickly once filming had finished.

Comedian Drew Carey shocked viewers today when he revealed his even thinner frame on "The Price is Right." Carey told his weight-loss strategy to People magazine: "No carbs," he said. "I have cheated a couple times, but basically no carbs, not even a cracker. No bread at all. No pizza, nothing. No corn, no beans, no starches of any kind. Egg whites in the morning or like, Greek yogurt, cut some fruit."