(Oct. 6) Fad diets are usually just that … fads. But the Atkins diet has outgrown that moniker.

Originally published in the early 1970s and most recently updated in 1997, the controversial low-carbohydrate weight loss plan has taken on market power that no fad could claim.

Food giants such as Britain’s Unilever PLC, which owns Slim-Fast Foods, are blaming the Atkins diet for a 23% drop in U.S. profits. It’s taking the credit for a solid beef market, low wheat prices and potato market woes.

Fads don’t carry that kind of weight, and even though economic experts and counter-trends such as the success of Krispy Kreme doughnuts show that not everyone buys into the power of Atkins, there’s no doubt it can hurt markets for carb-heavy items like potatoes and pasta.

Potato marketers are looking to combat bad Atkins press with a nutritional message about vitamin C, potassium and energy-boosting qualities.

That’s an important message to get out, and it can’t hit the airwaves and newspapers soon enough. If it is to battle growing consumer perceptions of potatoes as a “bad” food, the message must be compelling and pervasive.

And Atkins devotees — as well as those of other low-carb diet plans — don’t shun all produce. That’s a fact that other marketers must factor into their marketing messages. To do less would be to chalk the 5 a Day effort up to a fad.