NEW YORK (CNN/Money) - Americans who've pledged allegiance to low carb diets are in for a rude shock. According to a new report Monday, consumers aren't cutting down on carbs as much as they thought they were.

A study of 11,000 people by market research firm NPD Group found that virtually none were cutting carbs to the degree that the low-carb diet recommends.

Adults who have cut their carb intake are still eating about 128 grams of refined carbs a day on average -- about 20 to 25 grams of carbs higher than a low-carb diet recommends for weight loss, the report said.

Additionally, the report found that at any given time, about four percent of the population -- or 10 million Americans -- is following some version of a low-carb diet, such as the Atkins diet, promoted by the late Dr. Robert Atkins.

"Low-carb diets are a fad, just like the low-fat craze of the late 80's and 90's, the question is how long will it last," NPD analyst Harry Balzer said in the NPD's "Carbohydrate Consumption Patterns" report.

"In the meantime, every manufacturer will put out their version of low-carb products and Americans will try them because that's what we do, we like to try new things," said Balzar.

To be sure, foodmakers eager to take advantage of the explosive popularity of the low-carb diet, have flooded the market with products -- everything from low-carb Doritos to a 'One-Carb' Ketchup.

Atkins practitioners disagree that the low-carb diet is nothing but a fad.

"The fundamental difference between any low-fat diet and the Atkins diet is that people have discovered the Atkins diet and its benefits on their own and have chosen to follow it. It was not prescribed by the medical profession," said Dr. Stewart Targer, with the Atkins Physicians Council. "As more people see its impact, its following will continue to grow."

Others, however, are more skeptical of its staying power.

For instance, a separate study by marker research firm ACNielsen found that even though more people are trying a low-carb diet , an even higher number was once on a low-carb diet but is no longer.

Said Burt Flickinger, a consultant with the Strategic Resources Group, "When it comes to their eating habits, consumers will continue to choose the proverbial sin over salvation -- or fat and sugar -- over the lack of it."

"The low-card trend is just a blip and in no way represents a structural change in the way Americans eat," said Balzar. "If food companies want follow this trend for now, they should do it. If that means selling a burger without a bun, that's fine. But don't go reformulating your bun because this won't last."