Low-carb labels often use 'creative accounting'
Low-carb labels often use 'creative accounting'
By Judith Blake
Seattle Times staff reporter
If you're thinking of trying some of those low-carb products now flooding the market, you may wonder what's in them and how they achieve their low carbohydrate levels.
The chief way to find out: Carefully read the labels.
One way they attain lower carbs is through their method of calculation. Many of the labels list total carbohydrates, then subtract certain items from the total to arrive at "net," "effective" or "useable" carbs, often bannered on the front of a package.
Usually there's wording somewhere on the package explaining why the "total carbohydrate" and "net carbohydrate" amounts differ.
Some nutrition experts disagree with this calculating system. And since there's no legal definition of "low-carb" or any official way of figuring it, consumers are a bit on their own.
The "net" carb level often results from subtracting a product's grams of fiber and sugar alcohols, such as the sugar substitutes maltitol and mannitol, from the total carbohydrates.
Manufacturers reason that fiber, while technically a carbohydrate, is not absorbed by the body, so shouldn't be counted as a carb.
As for sugar alcohols, manufacturers say that while these also are technically carbohydrates and a source of calories (though fewer than sugar), they have a negligible effect on blood sugar, so also shouldn't count as carbs.
Here's a product example: A low-carb candy claims only 2 grams of "net" carbs per serving, after subtracting fiber (2 grams) and sugar alcohols (4 grams) from the total carbohydrates listed.
Such figuring draws a skeptical response from Adam Drewnowski, director of the University of Washington Nutritional Sciences Program.
"I think they're doing some creative accounting," he said.
Some experts would include sugar alcohols as carbohydrates, since they are absorbed, but would subtract fiber, which is not absorbed. Figuring this way, net carbs for the candy product mentioned earlier would be 6 grams, not the 2 grams claimed.
Since labels usually list both total carbohydrates and carbs from fiber and sugar alcohols, you can do your own calculations, based on which line of thinking makes the most sense to you.
Labels will also clue you in on other ways carbs are lowered, such as using soy protein isolate, wheat protein isolate or wheat gluten in place of wheat flour in bread, pasta and pancake mixes. These replace many of the carbs with protein, favored in anti-carb diets because protein does not raise blood sugar.
Also frequently used: sugar substitutes such as sucralose, which provide a sweet taste without sugar's carbs or calories.
As with any processed foods, you may also want to check labels for unwanted ingredients, such as trans fats (usually shown as partially hydrogenated oil), which are used in some products.
Comparing diets
Before trying a diet that limits carbohydrate intake to 20 grams a day, as one popular diet does, consult your doctor, advises Drewnowski.
Carbohydrates are essential to the body, and restricting intake to that level for more than a brief period poses a risk to kidney function as well as possible nausea and fatigue, he said.
A 20-gram daily limit for only a brief period — as in the first two weeks of the Atkins diet — probably would not pose a serious health threat but still merits medical consultation, Drewnowski said.
"I think it's better to check things out with your doctor," he said.
A less-severe daily limit of 30 grams slightly diminishes possible risks, he said.
To put those numbers in perspective, most mainstream nutritionists recommend that about 55 percent of daily calories come from carbohydrates. That equals 275 grams of carbohydrate for anyone consuming 2,000 calories a day.
Carbohydrates — essentially starches and sugar — supply energy and play a role in the functioning of the entire body, including the brain. Carbohydrates not used immediately are stored as fat, which converts to energy. When carbohydrates are severely restricted, more fat turns to energy, causing weight loss, low-carb advocates say.
Debate over carb cutting
While legions of Americans say they've shed pounds through carb-cutting, nutrition experts remain divided over these diets. Critics contend that dieters who have lost weight did so not because they cut carbs but because they trimmed calories. On this point, studies are mixed.
Both the low-carb and high-carb advocates agree, however, that it's best to get any carbohydrates from high-fiber, whole-food sources. Whole-grain bread, whole-grain pasta and brown rice, for instance, are favored over white bread, white-flour pasta and white rice. Refined (white) sugar — high in both calories and carbs but lacking nutrients — is discouraged by both camps.
Vegetables and fruits also contain carbohydrates, though usually much smaller amounts; they also pack essential vitamins, minerals and fiber.
Still unsettled is the impact of a low-carb diet on "good," "bad" or total blood cholesterol. Some worry about a possible negative impact on heart health because many low-carb diets allow or encourage eating lots of high-protein foods, including meats, cheeses, cream and other foods loaded with saturated fat.
Several recent studies have failed to show negative effects on cholesterol, however, surprising some experts. At least one study even showed a decrease in harmful triglycerides.
Experts caution, however, that the studies so far have been short-term. Long-term impacts on both health and weight loss remain unknown, they say.
Gaining weight on some low-carb diets is not unheard of, possibly because dieters — given permission to ignore calories and not worry about food's fat — go overboard on chowing down.
At the same time, many individuals say they're taking a moderate approach, trimming carbs but also watching their fat and calorie intake — in other words, eating less, as mainstream authorities have long advised.
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