Ever wondered if you could handle Beyoncé’s punishing workouts while maintaining her post-baby diet? What about sustaining yourself on Victoria Beckham’s regimented eating plan for a day?

Rebecca Harrington spent a year trying out these diets and 12 more celebrity eating plans, all in the name of science…er, comedy. Her new book, I’ll Have What She’s Having: My Adventures in Celebrity Dieting ($11, amazon.com) covers everything from the delicious (Gwyneth Paltrow’s “truly spectacular” fish tacos) to the gross (see: Greta Garbo’s celery loaf).

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Harrington, 29, tells Health that she started testing celeb diets after stumbling upon William Howard Taft’s “horrible but funny” diet online. From there, she moved on to Elizabeth Taylor’s eating plan and a writing project was born.

She tried to stick to each diet for 10 days. Each brought different, often hilarious challenges, and had varying results:

She found Beyoncé’s favorite plan to be the most effective for weight loss; she lost 10 pounds doing a combination of the Master Cleanse diet (which Queen Bey reportedly endured to lose 20 pounds for a movie role back in 2006) followed by the protein-packed eating plan Mrs. Carter followed after Blue Ivy was born.

Harrington says she gained weight while following Cameron Diaz’s regimen, but chalks it up to muscle gain from following the star's workout schedule.

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In following the eating plans of long-ago celebrities like Jackie Kennedy and Marilyn Monroe (which includes choking down two raw eggs whipped into warm milk for breakfast, then starving until a hot fudge sundae dinner) as well as present-day superstars like Madonna and Victoria Beckham (who once followed the Five Hands Diet, meaning she eats just five handfuls of food a day), Harrington was able to tease out a change of tides:

“In the past, diet food was abundant but disgusting. Now, diet food has smaller portions but is better tasting. I don’t know which is more humane," she says.

Regardless, Harrington wouldn’t recommend these diets to anyone. “I think they are all sort of insane for different reasons,” she says. “For some diets, the food is so disgusting you would not wish it on your worst enemy. For other diets, the food tastes good but is way too expensive. A woman can’t win!”

“If anything, I think it makes you feel quite grateful to eat like a non-famous.” We'll second that!

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