The M-Plan
Katy Perry and Kelly Osborne are fans of the M-Plan, a diet heavy in mushrooms, The Daily Mail reports. The diet claims it helps women shed fat in the waist, hips and thighs -- but not the bust. (Anthony Harvey/Getty Images)
Anthony Harvey/Getty Images
The Alkaline Diet
How does Posh maintain her super-slender physique? According The Mirror and other sources, it's with the Alkaline Diet. The goal of the diet is to achieve an "optimal pH balance in the body," by avoiding sugar, pasta, white rice, caffeine and meat, which cause your body to produce acid. (Mike Coppola/Getty Images)
Mike Coppola/Getty Images
The Vegan Cleanse
When Q Bee and Jay-z showed off their toned figures at the 2014 Grammy Awards, they attributed their slimmer bodies to a 22-day vegan diet. (Mike Coppola/Getty Images)
Mike Coppola/Getty Images
Macrobiotic
For four years, Gwyneth Paltrow preached the powers of a macrobiotic diet. The diet encourages grains and local vegetables as staple foods and prohibits highly-processed or refined foods. (Theo Wargo/Getty Images)
Theo Wargo/Getty Images
The Cabbage Soup Diet
Sarah Michelle Gellar likes to slay the pounds with a seven-day cabbage soup diet. (Jason Merritt/Getty Images)
Jason Merritt/Getty Images
The Perricone Diet
Celebrities, such as Julia Roberts, Cate Blanchett and Kim Cattrall, are fans of the Perricone diet -- a diet rich in lean proteins, antioxidants and omega-3s. The diet claims to have anti-aging benefits, The Daily Mail reports.
The 5-Factor Diet
Eva Mendes, Mandy Moore and Jessica Simpson have all tried the 5-Factor Diet, which revolves around the number five: You eat five-ingredient meals, five days a week, and complete 25-minute workouts, five times a week.
Weight Watchers
Jennifer Hudson and Jessica Simpson both counted points with Weight Watchers to shed the pounds. And both have been spokespeople for the company. (Dimitrios Kambouris/Getty Images)
Dimitrios Kambouris/Getty Images
