As consumers, we like to think of ourselves as savvy and rational. But marketers have always known better. The health food and dietary supplement industries, in particular, have long made a mockery of the rational consumer.

They delve into our wounded hearts with evangelical calls to detox and purify. They bend our minds with pseudoscientific drivel and armies of so-called experts who tell us that instead of fresh, nourishing food, we need supplements and specially treated products.

Never mind that mounting evidence suggests the contrary. Our self-control is subverted by clever ads and our rationality crumbles when everything from upscale health stores to 7-Elevens stock pills, powders and products that would make a snake oil salesman blush.

While we may be alert to crude promises of miraculous results, we’re not so good at sussing out the more insidious distortions and oversimplifications — especially when it comes to something as intimate as our bodies. Human emotions and self-delusion tendencies get in our way.

The stresses of modern life often make us feel out-of-sorts and tired. With so many of these stresses — overwork, tyrannical bosses, screaming toddlers — seemingly outside our individual control, it’s no wonder that we swallow the latest health fad.

Wouldn’t it be easier if our suffering were caused by some particle that we are eating or not eating? If jettisoning gluten was the answer? Or popping a multivitamin? Or eating like a caveman with a Whole Foods next door?

Consumers end up with little real idea of what we’re buying. Comedian Jimmy Kimmel recently featured a sketch asking health-conscious folks avoiding gluten what gluten actually is. They had no idea.

What we think we know about nutrition is often based on tenuous links and conflicting evidence. One day, egg yolks and butter are health villains. The next they are pardoned. Whole grains are either good for us or turning our brains into mush. Antioxidants are great — wait, they might accelerate cancer. Omega 3s prevent heart disease and boost brain power, or maybe they don’t.

To this confusion, add a heaping helping of outright lies and untested products. Then a dollop of distrust for medical professionals and academic authority, plus a generous serving of poor regulation and big money politics. Top it off with celebrity pitches and plugs from someone like Dr. Oz.

What you’ve got is a recipe for a public-health nightmare. Americans have been turning into do-it-yourself biochemists, unable to sort the bogus from the beneficial. Unfortunately, what we don’t know can hurt us. We are spending our money on products that are useless — or worse.

But could the tide be turning? There are signs that consumers may be starting to wise up and push back, forcing companies to listen.

Marketers, for example, have been telling us that we need foods and pills that are “natural” — despite the fact that the Food and Drug Administration admits it doesn’t have a clue what that term means.

Companies are finally getting socked with mounting legal challenges and deciding to drop misleading labels. Kellogg, for example, has just settled a class-action lawsuit over its Kashi “All Natural” and “Nothing Artificial” labeling. The company is paying $5 million to settle. It joins a growing list of familiar brands like Tropicana and Pepsico, which have learned that misleading consumers is potentially costly.

Of course, even if something comes from nature, it’s not necessarily good for us. Consider Testofen, an extract of the herb fenugreek manufactured by GNC and touted as “clinically proven” to boost testosterone. Recently, California and Delaware residents have countered these claims with a consumer fraud lawsuit including allegations under the Racketeer Influenced and Corrupt Organizations Act (RICO) that published studies have repeatedly shown Testofen has no such effect.

Fish oil is a perfectly natural substance, but for a Beijing man, this didn’t mean that a fish oil pill endorsed by former National Basketball Association star Yao Ming would help him with memory loss and poor eyesight, as manufacturers claimed. The pills didn’t work, and the man decided to sue.

Part of the problem is a serious flaw in our regulatory system. In 1994, Congress, at the strong urging of the supplement industry, passed the Dietary Supplement Health and Education Act (DSHEA), which allowed things like vitamins, minerals, herbs, amino acids and other products to be sold with exactly zero proof of effectiveness or safety.

The snake oil salesmen saw their opportunity, and corporate giants jumped into the game. The supplement industry alone, which has become a $30 billion behemoth, is fighting tooth and claw to preserve this dangerous system, conning the public with cries of “health freedom” and lining up against anyone, like Senator Dick Durbin (D-Ill.), who tries to introduce common sense legislation.

Meanwhile, a company like the supplement direct seller Herbalife, accused by short seller Bill Ackman and others of being a pyramid scheme, lavishes money on politicians from both parties in the hopes of keeping regulators out of its business. (Ackman has been criticized himself for lobbying members of Congress to crack down on Herbalife. But according to a Reuters article, Herbalife spent many times more on its own lobbying efforts in 2013 than Ackman did).

The good news is that despite regulatory failings, consumer activists have been rising to the challenge of food and supplement manufacturers that have been growing bolder with bogus health claims. Web-savvy consumers are finding reliable information about products through ConsumerReports.org, FDA.gov, and the NIH, along with blogs like Sciencebasedmedicine.org, founded and edited by Yale neurologist Steven Novella.

The high profile debunking of the gluten-free fad, for example, by the very doctor who first fingered the protein as a health worry has put TV doctors and celebrity health gurus like Gwyneth Paltrow on notice that science can sometimes triumph over sensationalism.

We’ll never be entirely rational when it comes to our yearning to be healthy, young and thin. But we still don’t have to swallow everything the health hucksters try to sell us.

PHOTO: REUTERS

PHOTO (INSERT 1): Bottles of spirulina are seen at Labiofam Laboratories in Jaruco outside Havana, September 6, 2011. REUTERS/Enrique De La Osa

​PHOTO (INSERT 2): A customer walks past organic products in an organic food chain store in Taipei June 30, 2009. REUTERS/Pichi Chuang ​

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