5 Celebrity-Endorsed Health Tips That Are Total Wastes of Money

"The supplement market is a billion-dollar industry," says Caulfield. "It's a huge part of the diet and fitness world." And yet, Caulfied says, there's "very little evidence" to support the idea that people with healthy diets should be taking daily supplements of any kind, let alone taking them by the bag-full like singer Katy Perry apparently does. "No one [trustworthy] believes that taking mega doses of supplements is a good idea," Caulfield says. "There is zero proof that mega doses improve health."

As for the idea that some supplements will make your sex life better or improve your IQ, let's hope you never believed them in the first place. The morale is: Save your money. Don't take supplements unless they're specifically recommended by your doctor.

To rid the body of "toxins," many health gurus are proponents of various detoxification plans, which typically come down to fasting and avoiding certain foods. It would seem like such a process would cost next to nothing. In fact, the detoxes and cleanses suggested by the Gwyneth Paltrow lifestyle site Goop often include rare (and very expensive) ingredients—to the extent that Shape magazine felt compelled to round up a list of cheaper alternatives to the Goop detox recipes. Meanwhile, the cost of 21-day cleanses that require little or no cooking might easily run $400 to $500.

The real problem, according to Caulfield, is that the body is constantly undergoing a natural cleansing process that doesn't cost a penny. "The organs in the body do this for us. When you pee, you detox," he says. Most importantly, "There is no evidence to support the idea that we should detox and cleanse. It's bogus." In his book, Caulfield offers an alternative cleanse, which he hopes readers will take to heart: “Cleanse your system of all the pseudo-science babble that flows from many celebrities, celebrity physicians and the diet industry.”

Women are constantly bombarded with celebrity trainers and assorted other "experts" offering advice about to get the flat stomach of Jessica Alba, the rock-hard arms of First Lady Michelle Obama, and the booty of Kim K or Jennifer Lopez. Often, the suggestions call for exercises that focus on one particular part of the body. Yet the commonly accepted concept of "spot reduction"—losing fat in one specific area through targeted workouts—is nonsense, according to Caulfield.

"You can't reduce fat on one part of the body," he says, no matter how much time, effort, and (possibly) money you devote focused to that specific part. "The way to have skinny arms, or to tighten your tummy, is to have low body fat" overall. Likewise, a comprehensive, full-body approach to exercise is healthiest. And sorry, there's no exercise in the world that will give you longer legs.

Before jumping to conclusions, let's state explicitly: Caulfield believes that there is nothing better in the world for people to drink than water. "Water should be your go-to drink, hands down," he says. Still, Caulfield points out that there is nothing scientific about the widely accepted concept that we must drink eight cups of water per day. Drinking lots of water won't reduce wrinkles or make your skin glow either.

"Just drink when you're thirsty," and you'll be fine, says Caulfield.

If that's all there is to it, then why is the eight cups myth still being circulated? Caulfield thinks the bottled water companies have a lot to do with it. Bottled water has been called the "marketing trick of the century," in that it costs 2,000 times more than a nearly identical product that comes out of the tap in your home. Americans spend roughly $12 billion annually on bottled water, and some of the biggest markups are for water brands endorsed by celebrities such as Jennifer Aniston, who has long been tied to Coca-Cola-owned smartwater.

"The change in your skin, phyisical (sic) and mental health is amazing! U won't go back!" Miley Cyrus Tweeted back in 2012. She was writing about switching to a gluten-free diet, and she was responding to critics who accused her of having an eating disorder. "For everyone calling me anorexic I have a gluten and lactose allergy," she wrote in another Tweet. "It's not about weight it's about health. Gluten is crapppp anyway!"

Caulfield begs to differ. "It's fair to say that there is absolutely no evidence that going gluten-free is healthier," he says. "There is no evidence that it's a good weight-loss strategy" either, according to Caulfield. People with celiac disease must avoid gluten, which is found in wheat, barley, and rye. But less than 1% of the population has celiac disease, whereas some 30% of U.S. adults in a recent survey said that they're trying to embrace a gluten-free diet. Caulfield assumes that a large portion of those going gluten-free believe that they have a sensitivity to gluten, or they perceive such a diet to be healthier. In fact, there are plenty of fast food menu items, donuts, cookies, and junk food snacks that have been slapped with the gluten-free label in order to jump on the fad, and they are certainly not healthy.

Caulfield says that his truth talking about gluten generates more hate mail than any other subject he tackles. "Some people go gluten-free or all-organic as a form of self-expression," he says. By questioning their motivations, and the science (or lack thereof) behind their decisions, he is essentially questioning who these people are as individuals. So it's no wonder people take offense. But it doesn't make them right about what is and isn't healthy.