Mehmet Ozs followers believe he is a trustworthy, serious-minded (and hot) physician. His equally fervent flock of critics say he is a fad-foisting, ratings-grubbing (and smart) TV celebrity. Which is it?In the 10 years since Oprah dubbed him Americas doctor, the 53-year-old Oz has shown he is comfortable in both roles.I just absolutely like him, says Maria Southard, 57, a food-service supervisor in the Philadelphia public schools. I believe what he says and repeat it at home and work.And its that unquestioning faith that health experts increasingly find troubling.Oz has become an actor playing the role of doctor, says Joe Schwarcz, director of the Office for Science and Society at McGill University, which fact-checks scientific information disseminated to the public.The problem with Oz is that he can be neither wholly trusted nor dismissed, Schwarcz explains. One day, he will offer a medically sound explanation of how hepatitis C attacks the liver; the next, hell proclaim that the syrup from an Andean root vegetable is the new secret to losing weight.The claims made on Ozs show often derive from some small experimental finding, says Schwarcz, then they run with it and convert what would be a 1-yard gain into a 99-yard touchdown.A spokesman for Oz, Tim Sullivan, says, We should have more faith in the viewer. Oz presents information, Sullivan notes, and trusts that his audience is sophisticated enough to judge its merits. The Dr. Oz Show, however, featuring props and simulations, often seems to more accurately resemble Wipeout than Charlie Rose. In a recent episode, Oz invited two participants to stand behind panels bearing life-size images of cartoonlike women whose bodies were slathered with yellow goop.Whats the secret to melt your fat for good? Oz asked. Its not about drastically cutting your calories or exhausting yourself with cardio. Im going to show you how to supercharge your hormones so you can melt your fat fast.He then hosed the goop off one of the panels.During the discussion that followed, Oz asked Natasha Turner, a Canadian naturopath, to explain how the supplements she has recommended adjust hormones to dispatch belly fat. I had never heard of this before I read Natashas book, Oz told his viewers.I just dont understand, says Schwarcz, how he can stand there nodding at the absurdities of what some of his guests are saying.Selling powerA distinguished cardiothoracic surgeon at New York-Presbyterian Hospital in New York, Oz is a Harvard grad who earned his medical degree at the University of Pennsylvania and an MBA from Wharton. He owns several patents and has written hundreds of articles in medical journals. Esquire magazine called him the most important and most accomplished celebrity doctor in history. Forbes ranks him among the top 10 most influential celebrities. And Time magazine has put him on the list of the 100 most influential people.One of his bestselling books, You: The Owners Manual, first published in 2005 and recently revised, has sold 2.7 million hardcover copies worldwide. His daytime TV show, now in its fifth season, has won four Emmys. His viewership has fallen 23 percent since 2011, according to the A.C. Nielsen Co., while two competitors, Dr. Phil and Ellen DeGeneres, have gained ground.Still, Dr. Oz ranks fourth among syndicated talk shows and averages 2.7 million viewers a day.On Feb. 4, the Oz media empire, which already runs a website, a blog and an active Twitter feed, launched a monthly magazine called Dr. Oz The Good Life.At 53, impeccably dressed, gym-rat fit and glowing with health, Oz holds himself to rigorous standards. He exercises regularly and fuels his body with blueberries, nuts and spinach-laced smoothies.Hes sort of an enigma, Schwarcz says. When he first appeared on Oprah, he was good. He talked about eating more vegetables and exercising. A steady diet of sensible advice, though, does not sustain ratings.When Oz promotes the benefits of raspberry ketones, garcinia cambogia, red palm oil, green coffee extract, strontium and Ayurvedic herbal remedies, he chooses his language carefully, using what Schwarcz calls weasel words such as may, might and could.Oz often notes that it is best to get nutrients from whole foods, and he urges consumers to check the purity and dosages of supplements. But since they are not well-regulated, labels may not be accurate.The show distances itself from the retail frenzy that inevitably results when Oz gives his generic blessing to a supplement.In May, he launched the Its Not Me campaign to disavow any link to products claiming to have his endorsement.Consequently, at a GNC store in a Philadelphia mall, the shelves stocked with items that Oz has praised are annotated with signs declaring featured on popular daytime health shows, and a wink.Explaining the shows wild swings from measured to hyperbolic, Sullivan says, Someone thats adversarial would call it inconsistency. We would call it diversity in programming.A clear example was the 2011 debate over arsenic in apple juice.That summer, after hearing concerns from consumers, a small advocacy group in upstate New York sent juice samples to a lab for testing. The results showed elevated levels of arsenic. In July, Food & Water Watch, a nonprofit based in Washington, put out a release on the findings.We wrote a letter to the FDA asking them to lower the acceptable levels, says the groups assistant director, Patty Lovera.Several weeks later, Lovera got a call from the producers inviting her to appear on The Dr. Oz Show.Ozs staff did its own study, sending three dozen samples to an independent lab for testing. The results showed that in 10 of the samples, arsenic levels were higher than 10 parts per billion, the limit set for drinking water.They really hyped it, Lovera recalls, adding that that was no different from most broadcast news reporters she had worked with. Its TV. Its what they do.The segment proved explosive. Were used to the food industry and the FDA blaming the messenger, says Lovera. But they really piled on Oz.The FDA has said that Oz failed to distinguish between organic and inorganic arsenic, when only the latter is harmful.On Good Morning America in September, physician Richard Besser accused Oz of fear-mongering. Besser, who went to medical school with Oz and served as acting director for the Centers for Disease Control and Prevention before joining ABC, said Oz was irresponsible for saying, We are poisoning our own families.You have absolutely no evidence that theyre doing that, Besser told him.But Oz held his ground, although in a later episode, he amended his message: I should have said, We may be poisoning our families. Even at the highest levels found in the samples, the arsenic did not pose the threat of acute poisoning. Oz, however, said his concern was chronic toxicity. Soon after, the FDA conceded that it had withheld some test results showing unacceptably high levels of arsenic in apple juice. A Consumer Reports study later confirmed the problem. And in December, Besser publicly apologized to Oz.A year and a half later, in July 2013, the FDA announced it was setting the limit for arsenic in apple juice at 10 parts per billion.Entertainment purposesWhile that outcome scored a victory for Ozs credibility, he lost points for the mixed messages.In the drumbeat for a segment about green coffee bean extract, for instance, Oz said, You may think that magic is make-believe, but this little bean has scientists saying they have found a magic weight-loss cure for every body type. When turned into a supplement, this miracle pill can burn fat fast.Yet, his site warns against this very sort of language.Avoid supplements that make miracle claims or seem simply too good to be true. If it says you can lose weight without changing your diet or exercising, thats also a red flag. Asked to explain the contradiction, Ozs spokesman says, Obviously, we didnt mean an actual miracle. You use language for descriptive and entertainment purposes.The author of the study that inspired Oz does not think green coffee deserves magical status yet.Dr. Oz just caused a floodgate of people thinking green coffee was going to help them lose weight, notes Joe Vinson, a chemistry professor at the University of Scranton. It is well-documented in animals, at least. But the consumer doesnt know the dose. The supplement industry is a Wild West.The pilot study, published in an obscure journal, involved just 16 people who got green coffee extract pills of varying doses or a placebo for 22 weeks. Vinson did not do the research. He was paid by Applied Food Sciences, an Austin-based company that makes the pills, to write up the findings.While promising, the study was tiny and brief, and Vinson says the subjects did not eat an American diet. And they came to the clinic frequently. They were monitored closely. It was not like free-living, see you in six months. It may be that green coffee extract helps people lose weight, but one would like to see multiple studies done.Of all Ozs claims, the most unverifiable has to be that men who have sex more than 200 times a year will reduce their physiologic age by six years.As with many of Ozs dramatic assertions, the science behind it is lacking.There is limited information available from scientific studies about an association between sexual activity and health, says Howard S. Friedman, professor of psychology at the University of California, Riverside, and co-author of the 2011 book The Longevity Project.While Ozs work as a surgeon he still operates once a week demands exquisite precision, his role as a TV celebrity does not.On May 19, 2012, Oz stopped in Philadelphia during a national tour offering free 15-minute physicals. The event, which drew 300 people, was held at Temple University.A television show is a bully pulpit, Oz told his audience. It gives you the chance to shout.