Yesterday, news broke that Atkins Nutritionals, the company that emerged from the low-carb diet craze of several years ago popularly known as the Atkins diet, filed for bankruptcy. What a difference a few years can make -- and what a lesson for investors about the power of fads.

You probably remember that several years ago, everyone and his brother were talking about "going on the Atkins diet" or some other low-carb variation. The buzz that buoyed this diet along: "Lose 10 pounds fast!" "You don't have to exercise!" "No salads!" And many of you probably heard some seriously weird stories about people eating some pretty nauseating amounts of protein-rich, super-fatty foods. Think of people scarfing down multiple McDonald's (NYSE:MCD) hamburgers sans buns and patting themselves on the back for "being on a diet."

Of course, given the focus on the nation's obesity problems, as well as our vanity and the siren song of weight loss with little effort, Atkins enjoyed a meteoric rise in popularity. After all, the Atkins diet has been around for decades, but it wasn't until several years ago that it reached the mainstream -- and quickly reached full-blown "craze" proportions starting around 2003.

Now that Atkins Nutritionals has filed for bankruptcy, it seems clear that the "craze phase" has passed, leaving the regimen in the scrap heap of discarded diets people remember by name, like Scarsdale. Of course, there are other forces at work, apparently. Copycat products, overspending on marketing, the loads of rival low-carb products on the market -- all of these led to the company's current state of demise.

Meanwhile, consider the public relations debacle when news agencies crowed that founding weight loss guru Robert Atkins actually died overweight and the fact that, well, it's pretty standard knowledge that fruits and vegetables have long been considered part of a healthy diet. Those probably didn't help business along, either.

However, as recently as last year, Atkins remained serious business as it toasted lots of companies' buns (or at least, the companies claimed it did). Interstate Bakeries, the name behind Twinkies and Wonder Bread, declared bankruptcy as many consumers turned their noses up at bread and sweets (it now trades on the Pink Sheets). Pasta was a high-carb no-no, and New World PastaCo. soon followed suit. Even the venerable KrispyKreme Doughnuts (NYSE:KKD) pointed the finger at the low-carb phenomenon, despite the fact that it became clear later on that the doughnut maker had more problems than carbs. PaneraBread (NASDAQ:PNRA) wasn't exactly moving and shaking, either, with bread having become a dirty word with so many consumers.

And of course, many food companies went out of their way to jump on the bandwagon, offering low-carb options of all stripes. Coca-Cola (NYSE:KO) and Pepsico (NYSE:PEP) both rushed to offer low-carb soft drinks like the low-carb Pepsi Edge, which is due to be discontinued by the end of the year. Ruby Tuesday (NYSE:RI) even adopted an Atkins-inspired section in its menu. Megacompanies such as Kraft (NYSE:KFT) and General Mills (NYSE:GIS) offered low-carb alternatives in grocery stores from sea to shining sea.

Here in Fooldom, many of us saw that the writing was on the wall in terms of the diet peaking as a craze -- the only question was when. This time last summer, Fool Tim Beyers wrote a contrarian piece highlighting high-carb stocks.Meanwhile, contributor Nathan Slaughter called it back in August, suggesting that the sheer overwhelming presence of the word "Atkins" and low-carb alternatives everywhere hinted that the fad was about to hit the skids.

It's difficult not to see the irony in Atkins Nutritionals having filed for bankruptcy just a year after the fad was reaching a fevered -- and ultimately unsustainable -- pitch. What great damage it did, though. Maybe it just goes to show that once you see something everywhere and hear everybody talking about it, the buzz has nowhere to go but down. Savvy investors can take advantage of such passing consumer fancies in the ways suggested in the articles mentioned above -- that is, if they have the nerve to go against the fad-driven crowd.

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Alyce Lomax does not own shares of any of the companies mentioned.