The proliferation of carbohydrate claims on food labels and menus should spur the Food and Drug Administration (FDA) to define "low-carb" and other carbohydrate claims, according to the nonprofit Center for Science in the Public Interest (CSPI).

While labeling rules exist for nutrient claims like "reduced fat" and "low-calorie," the FDA never defined "low-carb," "reduced carb," or "carb-free," which makes those claims illegal. But in recent weeks, manufacturers have started to flood supermarket shelves with foods that make implied low-carb claims like "carb smart," "carb aware," and "carb sense." Today the Grocery Manufacturers of America (GMA) asked the agency to provide guidance to food companies on low- carb claims.

CSPI agreed with the Grocery Manufacturers of America (GMA) that the FDA needs to set official "low-carb" levels. However, CSPI called on the FDA to:

• Regulate implied low-carb claims. The FDA should regulate claims like "carb counting," "carb fit," and "carb options" as though they were "low carb" or "reduced carb" claims.

"Consumers clearly buy those foods because they expect to get fewer carbs," according to CSPI nutrition director Bonnie Liebman. "If the FDA defines only 'low carb' claims, it will spin its wheels regulating a claim that few companies bother to use."

• Prohibit "net carb" claims. Manufacturers get "net carbs" or "impact carbs" by subtracting fiber, sugar alcohols, and other carbs that supposedly have "minimal impact on blood sugar."

"Is a carb that doesn’t raise blood sugar no longer a carb?" asks Liebman. "Should a company have to test a food to make sure that it doesn’t boost bloods sugar? The FDA should answer those questions and require all packages to follow the same rules. What if companies started deducting fats that don't raise blood cholesterol to get 'net fats,' or forms of sodium that don’t raise blood pressure to get 'net sodium'? The Nutrition Facts panel would become a zoo of competing numbers that would confuse and, in some cases, mislead the public."

• Require the words "not a low-calorie food" next to carb claims. Labels should alert consumers that foods with claims like "carb options" and "carb fit" are not low in calories (unless the food meets the FDA's definition of "low-calorie"). The FDA now requires a "not a low-calorie food" disclosure on foods that make "no sugar added" claims.

"Consumers need to know that 'minimal impact on your blood sugar' does not necessarily mean 'minimal impact on your hips,'" cautioned Liebman. "People assume that they can't gain weight on foods with claims like 'carb aware' and 'carb smart,' just as they assumed that 'fat- free' on the package meant 'fat-free' on your waist. It's a huge leap of faith to assume that the calories in a lower-carb food don't count."

CSPI suggested that a low-carb food should have no more than six grams of carbohydrates per serving and that the term "reduced-carbohydrate" be permitted for foods that have at least a 25 percent fewer carbohydrates.

"With two out of three American adults overweight and obesity rates surging in children and teens, the nation can't afford to let this carbohydrate craze add even more pounds to our bellies and backsides,"said Liebman.