Low Carb Products: The Low Down (cont.)
"When a product markets itself or is perceived as something that is useful for weight loss, and it doesn't have any fewer calories than the food it's meant to replace, from a weight-loss perspective there is no difference," say Linder. "And from a nutrition perspective a low-carb beer is not more nutritious or more healthful for you than a regular beer."
What Does "Low Carb" Mean?
Even though many products tout themselves as "low carb" or are marketed to "carb counters," the FDA has not legally defined what "low carb" means, as it has for low fat, low sodium, and low cholesterol.
Experts say that until the FDA decides to weigh in on the carbohydrate issue, it's up to consumers to educate themselves on how to interpret low-carb claims on product labels.
By law, food manufacturers are required to list the number of total carbohydrates in a product on the nutrition facts label. But makers of low-carb products often include another box next to the nutrition label that has information on the "net carb" content of the food.
The net carbohydrate content is designed to reflect the amount of carbohydrates the product contains that will cause blood sugar levels to rise, a key factor in low-carbohydrate diets such as Atkins and the South Beach Diet.
"There is no legal definition of net carbs. That's their math," says Lindner. "They have a formula about how the number of grams of carbs don't count the way you think they would count."
Registered dietitian Samantha Heller says that in calculating the net carbohydrate content, many food companies subtract the number of grams of dietary fiber as well as other carbohydrates such as glycerin and sugar alcohols from the number of total carbohydrates listed in the nutrition facts label.
"Their rationale is that the glycerin and the sugar alcohols do not raise blood sugar as quickly or as high as the regular carbohydrates," says Heller, who is a senior clinical nutritionist at New York University Medical Center. "Though this is true, they're choosing to ignore the fact that they still have calories."
Rather than relying on the manufacturer's math, Heller recommends that carb-conscious consumers look at the total number of carbohydrates in the nutrition facts label and then subtract only the dietary fiber in order to get an idea of how many net carbohydrates are in the product.
Unlike sugar alcohols, Heller says dietary fiber does not make a significant contribution to the calorie content of foods because it's not readily digested by the body.
When the sugars and starches that cause blood sugar levels to rise are taken out of foods that rely on these elements for flavor and texture, something has to take their place.
In the case of low-carb candy, ice creams, and other sweets, that often means sugar alcohols, such as sorbitol, maltitol, and lactitol.
"They have a very similar chemical structure as sugar, but they have alcohol attached to it, which regular sugar doesn't," says Mary Ellen Camire, PhD, a professor of food science and human nutrition at the University of Maine and a product development expert with the Institute of Food Technologists.