Why cleanses are so popular, even though they don't work

I am fascinated by this question, particularly as there are many reputable and easily accessible sources of health information that are unequivocal about the unproven nature of cleanses and detox diets.

The Mayo Clinic website, for example, notes that "they're not scientifically proven."

And WebMD, one of the single most popular sources for health information, notes, "Experts say they are neither necessary nor scientifically proven to work."

Yahoo! Health goes even further: "The claims that extreme detoxing will rid your body of toxins, give you more energy and melt away pounds aren't true."

But the truth never takes. On the contrary, the popularity of cleanses-and, for that matter, all trendy diets-seems to be growing.

A big part of the story, of course, is that celebrities are vocal supporters of the trend. Celebrities are also under intense pressure to look a certain way. They are both desperate consumers and ardent purveyors of dieting fads. And because they look so darn great, it's easy for the unwary to conclude that cleansing works.

But more must be going on. The evidence against the value of cleanses is just so undeniable and the whole concept so silly, it seems unlikely that celebrity endorsements alone would be enough to keep this pseudoscience thriving.

I asked Walter Willett, professor of epidemiology and chair of the Department of Nutrition at the Harvard School of Public Health, to speculate about the continued interest in cleansing despite the clear lack of evidence.

His guess: "It is possible that taking a break from the steady overeating that is the norm for most Americans could have some benefit and make people feel better."

I think he is on to something. I do think people view cleanses as a break.

But I would take it even further than Willett. I am speculating here, but I think one of the reasons cleanses have so much traction is that they are more than just a break: they are viewed, consciously or unconsciously, as a way to pay for our lifestyle sins.

Cleanses are a form of self-flagellation. They are a short-term atonement for bad nutrition choices and consumption excesses. Many celebrities, including Gwyneth, often frame cleanses in these terms, as retribution for holiday indulgences, for example.

Gwyneth seems to go on a cleanse every January. ("It is that time of year, folks. I need to lose a few pounds of holiday excess. Anyone else?" she wrote on her Goop website on December 31, 2008.)

Adding to the penance vibe is the reinforcement you get from friends and even strangers. With few exceptions, they offered words of encouragement. I got many in the vein of "Good for you" and "Hang in there."

Nobody laughed at me or told me I was nuts. It was generally perceived as a righteous activity, like recycling, driving an electric car, or commuting on a bicycle in the middle of winter. There is also a massive sense of accomplishment when you finish.

The mountain summit reached. The marathon completed. So even though the cleanse has no real health benefits, you have a sense that you have done something, which likely adds to the placebo effect that leads one to feel pure, happy, and clean.

I've experienced this feeling of triumph over starvation before. When I was fourteen, my older brother, Case, dared me to stop eating. Actually, it was more of a sibling rivalry-fueled contest than a dare. It was summer vacation. We were bored.

And Case was reading Alive, the book about the soccer team that crashed in the Andes.

The survivors were so desperate for food they ate their dead teammates; hence my brother's no-food fixation. Case figured we should give it a try-going without food, that is, not eating human flesh.

The rules for our little game were simple: whoever goes the longest without food wins the contest.

I wish I could report that I outlasted my big bro, but, alas, it was a tie. After two full days and much moaning and quarreling, we came to a mutual agreement to stop. (It is hard to imagine a parent of the current hypervigilant variety allowing this to continue beyond morning snack time. It was a different time, as they say.)

I vividly remember three things about this tournament. First, I really thought two days without calories was a significant achievement. Second, the first thing I ate when we threw in the towel was an entire row of Chips Ahoy cookies, which I am fairly certain would not be a Gwyneth-approved postcleanse strategy.

And, third-and this is the reason I relate this story-I got a buzz out of the experience.

The popularity of cleansing may be tied to this kind of psychological pick-me-up.

It has been noted in some clinical studies that individuals in the first stages of starvation often experience a heightened sense of well-being or bliss. (Note: During my Gwyneth-inspired cleanse, I never felt anything close to euphoria or bliss or even well-being.)

For those who experience it, the sensation may be the result of the release of endorphins associated with extreme calorie restriction. Starvation will do that.

Of course, the other reason they are so popular is that they lead to short-term weight loss. I lost weight. Again, starvation will do that.

Excerpted from "Is Gwyneth Paltrow Wrong About Everything? How the Famous Sell Us Elixirs of Health, Beauty, and Happiness" (Beacon Press, 2015). Reprinted with permission from Beacon Press.