Journalists are guilty of spreading this particular rumor even more than celebrities themselves. Think of the number of magazine cover stories that start with the line, "She was completely makeup-free and looked gorgeous." The likely truth, however, is that the star was wearing very strategic makeup. "It takes a lot of time and attention to get the 'no makeup' look," says Suki Kramer, founder of natural skin care line Suki. "It actually takes more time to look like you're not wearing any than to get the glam look." After all, how many women -- beautiful celebrity or not -- would show up to an important interview completely barefaced?

When Lady Gaga appeared on the October 2011 cover of "Harper's Bazaar" without makeup, she explained in the interview that it's not as simple as washing your face and posing for a picture. "There's this idea that it's all natural, but everything's been staged to look natural," said Gaga. "Don't you think that what's on the cover of a magazine is quite artificial?" At least she's willing to admit it.

Most celebrities don't flat-out deny wearing extensions, so this one is more like a lie by omission. But it's important to acknowledge that the looks we see on the red carpet are the result of hours of professional styling and countless products, hairpieces, and enhancements.

When it comes to hair growth -- which scientists estimate at half an inch per month -- celebrities appear to be setting records. Remember when Katie Holmes got tired of her bob haircut? It transitioned from short to super-long in a matter of weeks, not years. Since that's pretty much impossible, she was almost certainly wearing extensions to add the extra inches.

The postpartum bounce-back rate among celebs is incredibly fast, with models like Gisele and Heidi Klum winning the race. Six weeks after giving birth to her son Benjamin, Gisele was back to pre-baby shape, telling "Vogue" that she hadn't exercised much and saying, "I think it was muscle memory."

When asked what a "normal" amount of time to get back to your pre-baby figure would be, Erika Schwartz, MD, an expert in hormone therapy, starts with the ideal scenario: "Without complications during birth, if a woman follows a healthy diet, increases sleep to 8 hours a night, and gets exercise three to five times a week while breast feeding for an average of three months," she says, "it takes about eight months to a year." She also warns that if you don't take care of yourself, you may never get back into shape.

While Gisele may have literally bounced back into shape, many celebs turn to extreme workouts. Kate Hudson reportedly exercised three hours a day after her first baby, and Halle Berry worked with trainer Ramona Braganza, using the 321 Baby Bulge Be Gone method and putting in at least an hour a day.

Alicia Silverstone is just one of many enthusiastic vegans in Hollywood, and she gives her diet full credit for her appearance. But swapping turkey for tofu isn't necessarily the healthiest route for you. "You need to listen to your body," says Frank Lipman, MD, founder of Eleven-Eleven Wellness Center in NYC. "Some people do really well on a vegetarian diet, but some people just aren't meant to be vegetarians. If you're not feeling vital every morning -- your skin should look good, you shouldn't have bloating and fatigue -- then whatever diet you're on is probably not for you."

Beyoncé famously used the Master Cleanse to drop 20 pounds before filming "Dreamgirls." "I lived on water, cayenne pepper, and maple syrup for 14 days," she said. "It was tough; everyone was eating and I was dying." Gwyneth Paltrow and Naomi Watts have both professed their love for Organic Avenue juices. But it's important to know that not all juices are created equal. "Juicing is a great way to get nutrients into your body -- but drink green juices," says Lipman. "A lot of the juices are too sugary." Fruit-based juices can actually cause you to gain weight, and Beyoncé's Master Cleanse juice had hardly any nutrients at all -- not exactly a healthy way to lose weight.